# Suspension Fork Experience - What's Working? What's Not?



## ds2199 (Sep 16, 2008)

Recently I have had a few converstions about suspension forks on a tandem. I would be interested to hear people's experience with their existing set up.

1. What fork make/model and what frame make/model?
1a. single or dual crown
1b. lock out?
1c. axle type 20mm thru? 9mm QR?​2. Team weight?
3. Type of riding.
4. Any feedback regarding performance, maintenance etc. (positive or negative).

I think this type of information on this forum would be extremely valuable.

Also, feel free to add anything that I missed. And don't be bashfull telling us if you are running a "non-tandem rated" fork. This is an informal poll - you can always hide behind your screen name...

Thanks!


----------



## ds2199 (Sep 16, 2008)

I guess I'll start

1. 2009 Marzochi 55ATA on a Ventana ECDM (full suspension)
1a. single crown
1b. has "lock out"
1c. 20 mm thru axle
2. aprox 270
3. we ride jeep roads, twisty singletrack, rocky trails (just about anything that I'd ride on my single bike - but no BIG drop offs).
4. fork has worked out well so far despite unfavorable reviews on Marz forks. We have about 2500 miles on the fork (seals replaced this past spring). 20mm axle works very well and is actually a form of quick release.

For as much bad press as I have received on the Marz forks, I have been pleasantly surprised with the performance of the fork. My local shops are all big Fox fans.


----------



## DaleTR (Apr 6, 2007)

*Fox*

A great Thread Idea. We are definitely in the "non-approved" bunch...

1- Fox 36 Talas RLC 160mm on Ellsworth Witness
1a - Single Crown
1b - Lock out - yes (used SELDOM - Only for LONG road sections)
1c - 20 mm QR
1d - 203mm Disc rotors/Hope Mono M6 calipers
2 - ~300 Team/50 lb bike
3 - Mostly Colorado Singletrack, up to "moderately" technical, PLENTY of Rocks, lots of tight/twisty.
4- Performs REALLY well. Stiff and tracks well. Think a 20mm thru axle is a requirement on a tandem. Replaced a Rock Shox Pike 454 (32mm stanchions..) and the Fox was a HUGE improvement in steering response and precision. A huge confidence boost. Good adjustability, the low speed damping adjustment REALLY helps keep the wallowing from the big bike under control. Holding up fine so far. 2 seasons on it, not a huge amount of hours on it, getting due to have seals done, but holding air pressure well, no oil leaks so far.

Been VERY happy with the Fox, and have NO complaints.

We have had the chance to ride a Mazzochi 55ATA on a friends Ellsworth Witness back to back with our Witness/Fox setup. The Marzzochi seems a bit stiffer than the Fox, noticeably more tracking precision. A gazzillion adjustments. I'll try to get him to post up...


----------



## PMK (Oct 12, 2004)

I'll post details later about what we ride...

To help others, why not also add your setup parameters if possible. Compression setting, rebound, spring or or air pressure, type terrain and team weight, chassis would be nice help also.

Just a thought.

PK


----------



## Mr.SBC (Dec 18, 2006)

1- Old Marzocchi DJ
1a - Single Crown
1b - No lock out (Wish we had it)
1c - 9mm QR
1d - 203mm Disc rotors/Hope Enduro 4 pistons
2 - ~350 Team/50 lb bike
3 - Mainly just Iowa singletrack right now, we have done a small amount of 1-2 foot drops, stairs etc.
4- Good fork, much better ride then a rigid fork. Wish it had a lockout though, while standing it bobs like crazy.


----------



## Blaster1200 (Feb 20, 2004)

DaleTR said:


> 4- Performs REALLY well. Stiff and tracks well. Think a 20mm thru axle is a requirement on a tandem. Replaced a Rock Shox Pike 454 (32mm stanchions..) and the Fox was a HUGE improvement in steering response and precision. A huge confidence boost. Good adjustability, the low speed damping adjustment REALLY helps keep the wallowing from the big bike under control. Holding up fine so far. 2 seasons on it, not a huge amount of hours on it, getting due to have seals done, but holding air pressure well, no oil leaks so far.


I was planning on building a hardtail tandem using a Pike 454 that I already have. Could you explain a little more why the TALAS is better?


----------



## Mr.SBC (Dec 18, 2006)

Im not sure about the talas, but I know the Pike is not "tandem rated"


----------



## Blaster1200 (Feb 20, 2004)

Mr.SBC said:


> Im not sure about the talas, but I know the Pike is not "tandem rated"


I don't believe any Rock Shox or Fox fork is tandem rated. In fact, they specifically say not to use their forks on tandems.

"FOX bicycle products are not designed or manufactured for use on any motorized bicycle, motorized cycle or motorized vehicle or for use on any vehicles carrying more than one operator/rider. Any such use constitutes misuse, which may result in serious injury, death or property damage, and will void all FOX warranties."


----------



## ds2199 (Sep 16, 2008)

I am very interested to continue to hear ALL experiences with suspension tandem forks. 

The whole point of this topic is to hear what is working and what is not. I know for a fact that many people use components that ARE NOT tandem rated. Many of them ARE up to the task. I realize that many component manufacturers do not care enough about the niche that is tandems let alone mountain bike tandems. 

I am not endorsing nor encouraging the use of Non-tandem rated items. I AM interested to real world experience (tandem rated or otherwise).

Please continue to share - Thanks!!!

I suppose someone like Alex will chime in at some point and let people know the list of tandem rated forks (I think it may be a pretty short list).


----------



## DaleTR (Apr 6, 2007)

*Pike*



Blaster1200 said:


> I was planning on building a hardtail tandem using a Pike 454 that I already have. Could you explain a little more why the TALAS is better?


Purely Stiffness & steering precision. The Pike (even with the 20mm..), while reasonable, tended to flex and "wander" a LOT more than the 36 TALAS under hard cornering or banging in the rocks. Until I made the switch I was pretty happy with the Pike, but was just looking for a bit less flex, and figured the bigger stanchions and beefier crown would help, and it made even more of a difference than I imagined.

The TALAS seems to give more tuning options as well. even with an "extra Stiff" spring in the Pike, the sag and low speed compression was more than I liked, probably contributing to the feeling of flex...

I think the Pike would be fine if your riding tends to the less rocky or less twisty side, but was getting overmatched on tight & rocky stuff.


----------



## TandemNut (Mar 12, 2004)

ds2199 said:


> I suppose someone like Alex will chime in at some point and let people know the list of tandem rated forks (I think it may be a pretty short list).


I was going to stay out of this one in the hopes that folks would provide more info without fear of the "fork police" making comments about various forks being approved for tandem use. However, since you mention it, here's the (short) list of forks still in production:
White Brothers Magic 100T (dual crown) and Groove 180 & 200.
ATC Racing T-5
Marzocchi 66, 55, DJ and 4X.
Rockshox had no particular concerns with structural integrity of their Boxxer forks, but would not warrant the internals under tandem loads. Some will recall this fork was spec'd on Cannondale tandems for a couple of years.
Risse Trixxy & Champ
Manitou Circus (DJ style) and Dorado.
Sad, ain't it?


----------



## befoot (Mar 11, 2006)

1. Cannondale Moto Fork w/red springs
1a. dual crown
1b. No lock out
1c. 9mm QR

2. Team weight...about 325 LBS
3. Type of riding....Single-track and forest roads lots of rocky spots
4. I like this fork but its only one I've tried on on our Cannondale so I don't know any better.
its gotten us down some very rocky downhills safe and sound 
as far as maintenance its very easy to rebuild although finding parts that's much harder (anyone have brown springs...or feed back on red vs brown springs?) 

ds2199, thanks for this post should be very helpful 
also...could you guys add what forks you used in the past and how they compare to your current setup? 

Thanks


----------



## drdoak (Feb 7, 2005)

1. 2010 Fox TALAS 36 RC2 (FIT cartridge) on a Ventana ECDM

- Single crown, 1.5" steerer tube (straight not tapered)
- No lock-out. Not needed for seated climbing, but very hard to coordinate standing climbs because of the fork bob. We do stand individually and find that acceptable.
- 20mm thru-axle (love it)
- 203mm disc rotors, Avid BB7 brakes

2. 270 lb team weight + 50ish lb bike (never weighed the bike)

3. Aggressive XC, rocky singletrack, desert trails, fireroads. Just about anything without big drops and tight switchbacks (or we'll walk those). Usually long climbs with long descents (average ride has 5000'+ ascent/descent). I'll ride more technical trails on the tandem than I would on my single because of the tandem's stability.

4. I absolutely love this fork. Travel is adjustable with the turn of a knob between 4", 5", and 6" (100-130-160mm). For almost all riding we'll use the 5" travel. If it's a long smooth climb I'll drop it to 4". If it's really nasty I'll up it to 6" but handling can get a little sluggish like that. Very stiff, confidence-inspiring fork because of the 36mm stanchions, 20mm thru-axle, and 1.5" steerer tube. Maintenance heavy, though, need to service dust wipers every 15-30 hours and change oil every 100 hours (6 months for us). 

Sometimes I'll start to think this fork isn't doing much because I never feel it move. Then I'll ride my single bike (Reba 29er) and it's a world of difference. The TALAS just soaks up everything. Deep ruts, rocks, roots... we just float over them. Very happy with this purchase.

Thanks for this topic. This is our first suspension tandem so I have no other forks to compare.


----------



## clj2289 (Jan 2, 2010)

We are pretty happy with the White Bros Magic 100T. Bike: 50lbs-ish, us: 270lbs, tools,water and etc: 20lbs? 
We are running a Fandango 29er hardtail, fork is at 50-60 psi. I would say we ride pretty aggressively. I like to take chances on the trail, but I am not comfortable doing that AND running non-tandem rated forks..Just my 2 cents.


----------



## banks (Feb 2, 2004)

Maverick DUC32 is tandem rated if correctly setup. I have a client that has 2 tandems with DUC on the front; Ventana 26" and Eriksen 29" hardtail. I have a bit of time setting them up and he will not look towards any other fork.


----------



## ds2199 (Sep 16, 2008)

banks said:


> Maverick DUC32 is tandem rated if correctly setup. I have a client that has 2 tandems with DUC on the front; Ventana 26" and Eriksen 29" hardtail. I have a bit of time setting them up and he will not look towards any other fork.


I've heard good things about the DUC 32 - too bad it is out of production for now. There's been rumors of a carbon version but that's going on almost 2 years...

Damn... Ventana 26 AND Eriksen 29?... is that Chuck and Karla?


----------



## B-radical (Oct 1, 2007)

My brother and I ride a Scott aluminum hard tail here in CO ( just not enough as we are oppisite sides of the state. We have a Rock Shox Argyle single crown w/ 20 mm. It has only 4" travel but tracks well. It has steel stanchions and special springs. Works well as we are 360# of riders plus gear. we also use Avid code brakes that are amazing. The Fox 36 should be a great fork w/ the big stanchions and air assist, would probably use the Van model w/ coil spring. 20 MM is the only way on mtn tandem unless you are pretty light riders.


----------



## PMK (Oct 12, 2004)

Several bikes to comment about. 380 pound team.

1998 Cannondale MT 3000. Moto fork, 100mm with 9mm QR axle. Non disc brake version. Fork has oem valving, but has been modified as follows. Fork boots from lefties, Ohlins suspension fluid, coil spring is oem but the elastomer has had a section of Judy elastomer machined to fit the upper spring end.

Preload run full firm, fork work very well, minimal if any flex is noticed, turning to steering stop allows almost 90 degrees of motion per side.

Fork requires special tools to work on it easily. Normal stuff gets accomplished, rollers lubed with Phil Wood oil, cartridge fluid replenished as needed. Had one lower triple clamp crack at the bolt hole, no failure, blended away the crack and check it frequently. The clamp is a documented problem from long ago. The on the fly adjustable rebound is sometimes utilized for different terrain.

Our 2001 MT800, I installed a Manitou Sherman single crown with 20mm axle, travel is adjustable (110mm / 150mm), but we always ran it in 110mm setting, 150 was to slack on the headtube angle. Changes made, swapped spring to extra firm, replaced damper fluid to 10 wt Motorex from oem 5 wt Motorex. Fork worked well but was used only for less than fifty miles of use, some jeep road some technical single track. Not a bad fork, but I would personally like more ramp up or progression for better mid stroke / bottoming control.

ATC, with 20mm and Avid BB7, 100mm of travel. We have ridden one while installed on our MT3000, double red springs, as delivered it had no amount of spring preload, added 10mm (?) of preload, this held the front up much better. The fork was a bit under damped for us, replaced damper fluid to 20wt. Good turning radius. The lack of external adjustments was acceptable, but made on the trail tweaks tough. Once dialed in, this was an obvious replacement for the Moto when needed. This fork was tested on technical singletrack, hardpack, sand, and other varied terrain.

We are now re outfitting our "squadron", one of our latest rides is an ECDM, it too has the ATC 100mm fork with a 20mm axle, Louise (210mm?) brake. Like the other ATC we tested, steering precision is very good, turning radius also. I need open this thing up, but speculate it has a pair of red springs (had at least one when I checked the tire to triple clamp clearance with the fork cap removed). Preload currently installed is about 8mm. This fork could use a bit more damping, it will likely also see 20wt fluid as the other fork did.

Our Fandango 29'r is here and I'm working to get it built, it too will have the ATC fork with 20mm axle and an Avid BB7 203mm disc. We have not ridden at great length any other forks on a tandem. 

I have installed a Fox40 onto the MT3000, planning to shorten the stroke to 100mm, unfortunately the triple clamp / lower leg offsets did not allow ample turning radius for where we ride.

I also have a Marzocchi drop off triple, modified from 170mm to 110mm of travel. I did install this onto the MT800 but other parts of the bike were not finished, the Manitou was fitted since the forks steerer tube was a more proper length. This fork has decent turning radius, is easy to work on, is spring with air over oil, open style damper with internally adjustable rebound. I believe this fork should work decent, provided the rigidity is ample for good steering precision, but again I have not run it. 

The present focus will be on further dialing in the ATC's, since this is our current setups for the most part.

In my opinion, one of the greater challenges is finding proper springs for these forks at the loads we run them. Also, some of the forks, based on single bike test, do not have much if any progression to the spring via an air column. Obviously flex is a concern, also, but is always a trade off against weight, unless you run and air spring fork setup.For some teams this may be very important.

PK


----------



## Team Fubar Rider (Sep 3, 2003)

We've been using a Rock Shox Argyle 318 (their DJ fork) on our C'dale tandem for about a year and a half with good success. I think for any teams over 300-325 lbs. it might be under sprung even with the extra firm spring in it. We're right at 300 lbs. and it is fine, but I know if it is much more, it won't be without some custom springs.

The thing about the RS Argyle is it has steel stanchions (stiffer than the alu ones on the Pike/Revelation/etc.) a 20mm Maxxle, and a lock out. If I did it over, I'd probably go with the 409, that is an air sprung fork. for more adjustability.


----------



## Trails4Two (May 12, 2008)

*Forks*

Clan McKim: Team weight 300lbs

1998? - The first fork we tried was a "Bad Betty Bombshell". It was on a Da Vinci tandem we demoed. To be fair, it was set up for a different team, but it did not move much at all. It looked massive and cool but not so functional.

2001 - Next came a 100mm travel Cannondale Moto (tandem version). It had red springsand quick release. I looked for brown ones but was told that not all tandem springs were actually brown...gave up and stuffed some extra elastomers inside the spring to firm it up. The fork worked really well, handling some serious abuse with minimal deflection or flex. We blew up a retaining clip and sprayed little roller bearings all over the inside of the fork. Fortunately we could still get the fork rebuilt by Cannondale. It started with hydraulic rim brakes and survived a conversion to discs. It now is in use by my in-laws and family as a "dirt-road" tandem, and still works well.

2006 - With our new El Conq we got an ATC fork. It started at 100mm but I ran it most at 125mm. This fork drove me nuts. From day one it had major sticking problems, eventually getting bad enough that it would "lockout" from stiction during a ride. I tried every combination of tightening bots/loosening bolts/lubing/cleaning that I could think of. I even sent it back for a full rebuild by ATC (got a story about the sticking being due to the color of the lower legs, not kidding..). This was a 20mm thru axle and rode very confidently - very stable and solid, it just didn't move right. I fixed it as best I could and sold it since my stoker was tired of hearing me b**ch about it.

2008 - Marzocchi Jr. T. The first big ride we did with this fork was Monarch Crest in Colorado. I couldn't stop laughing. Every time I hit a bump/drop/roller I broke out in joyful whooping. This fork is huge 170mm travel, 20mm thru axle and very smooth. It was way too soft out of the box, but the addition of the air preload caps quickly fixed that. It could probably use a servicing and maybe a touch heavier oil to increase damping. It is amazingly supple, but will bob quite a bit on hard flat peddling. Honestly I want about a 140mm fork, but in the Tandem rated world there is not much and out here in Grand Junction I would rather use too much fork rather than too little. The folks at White Bros told me they could modify something for me, but I would need a job first.

2010 - To be fair to ATC, I test road a Ventana at AORTA that was specced with an ATC. I was really curious as to how a different fork would ride. It was much better. Some very slight sticking, but nothing substantial. The Ventana with the ATC felt "zippier" than the one with the Marzocchi.


----------



## Blaster1200 (Feb 20, 2004)

Along the lines of this discussion, what would you all consider as the ideal amount of fork travel on a rigid rear tandem, and why?


----------



## Trails4Two (May 12, 2008)

*travel*

I think it will vary quite a bit depending on riding style and terrain. For us I really think 140-150mm would be best, but I've never tried a fork with that travel so I'm just guessing. 100mm is the minimum I would try.


----------



## Blaster1200 (Feb 20, 2004)

Trails4Two said:


> I think it will vary quite a bit depending on riding style and terrain. For us I really think 140-150mm would be best, but I've never tried a fork with that travel so I'm just guessing. 100mm is the minimum I would try.


Oh, yeah...riding style...It really depends on what my wife will tolerate.  We don't have a tandem yet, but I'm working on that, so we don't have any experience on a tandem. I race DH and BMX at an expert level (even at age 41), but my wife is a little more conservative, although she does ride BMX and DH (yes, even at Whistler!). So that means her comfort level will be the limit of technical terrain and speed. We may later move to a full-suspension frame. For her comfort, I already did pick up a Thudbuster seatpost.

As mentioned above, I was planning on using a Pike, but set at 125. I also have a Fox 36 Float I can use. The reason I need to pick the travel is that I want to design the frame around a particular travel. Of course, I can deviate from that a bit, but I want to at least have a target in mind.

This has been an informative thread! Thanks to all who've replied!


----------



## Trails4Two (May 12, 2008)

I'd pick a general 125mm travel to build the frame around. If you need more travel, remember that with a longer wheelbase more travel has less effect on head angle than on a short bike.


----------



## drdoak (Feb 7, 2005)

Blaster1200 said:


> Oh, yeah...riding style...It really depends on what my wife will tolerate.  We don't have a tandem yet, but I'm working on that, so we don't have any experience on a tandem. I race DH and BMX at an expert level (even at age 41), but my wife is a little more conservative, although she does ride BMX and DH (yes, even at Whistler!). So that means her comfort level will be the limit of technical terrain and speed. We may later move to a full-suspension frame. For her comfort, I already did pick up a Thudbuster seatpost.
> 
> As mentioned above, I was planning on using a Pike, but set at 125. I also have a Fox 36 Float I can use. The reason I need to pick the travel is that I want to design the frame around a particular travel. Of course, I can deviate from that a bit, but I want to at least have a target in mind.
> 
> This has been an informative thread! Thanks to all who've replied!


I'd use the 36 Float, and probably all of the travel or reduced to 130-140mm. I am not sure how much tandem experience you have, but with your background and a trusting wife you could really have some fun with the stability of the tandem.

We run a 36 TALAS, 100mm = quicker handling, not as plush, 130mm = happy medium, 160mm = sluggish steering, but float over everything. Other than steering, I don't notice any difference in overall bike geometry, compared to a single bike where an adjustable fork can totally change how the bike feels.


----------



## PMK (Oct 12, 2004)

drdoak said:


> 1. 2010 Fox TALAS 36 RC2 (FIT cartridge) on a Ventana ECDM
> 
> - Single crown, 1.5" steerer tube (straight not tapered)
> - No lock-out. Not needed for seated climbing, but very hard to coordinate standing climbs because of the fork bob. We do stand individually and find that acceptable.
> ...


Have you posted a photo of this bike overall and maybe with some detail photos somewhere on the net? I would like to see some photos of it.

Thanks
PK


----------



## PMK (Oct 12, 2004)

With some rides on our ATC forks on both the Fandango and ECDM, I'm learning what I like and dislike about these forks. Consider also I spent some miles on a loaner fork that was installed on our MT3000.

As mentioned, we now own two ATC forks, one installed on our Fandango 29r hardtail and the other on our ECDM later model series with the rear shock upright and parallel to the seatube.

On both bikes we run 20mm axles.

One bike has Magura Louise discs while the 29r uses BB7's.

What is good about these forks&#8230;

As I mentioned in a previous post they are very good in steering precision and not flexing. This is probably based on the fact of them having large diameter tubes.

No flex is noticed while rolling, this includes brake forces trying to bend the fork aft, or twisting flex from steering inputs or on a result of deflections.

The fork has merit in its modular machined construction.

The design is a dry type fork, with no oil bath for the telescopic tubes. These are lubricated via grease ports.

Seals are easily cleaned on account of the sealheads being threaded onto the outer tubes.

Bushings are a finger fit and requiring no special tools.

Fork travel settings can be varied by spacer location changes from a top out or negative position to positive positions, or if additional travel can be utilized, spacers may be left out. This is also how axle to crown dimensions can be dialed in to obtain manufacturer head angle and trail dimensions.

Being a dry fork design, major fork leaks are minimized to non existent. Also the damper cartridge is on the side opposite the disc, so even if it were to leak, the disc should remain uncontaminated from leaking fluid.

Things to not like about these forks&#8230;

First off, many folks have complaints about the forks being notchy as they move through the stroke.

Some have complained about knocking sounds during fork movements.

From experience, I do not like servicing the fluid in the damper. Having worked on motocross suspension setups since the mid 70's, I still do not have enough experience to easily bleed one of these dampers to my satisfaction unless I modify the damper.

The triple clamp design is not conducive to proper torques needed to secure the fork tubes.

The fork bridge mounting, like the triple clamp pinch bolts is not proper for good clamping to the outer tubes.

By design, the bottoming cushion is placed to impact the damper seal with no support or protection to the seal.

A minor concern is no easily removed front wheel.

For some, the lack of compression, rebound, lockout or on the fly travel is a concern.

So there you have some thoughts on good and bad. Thing is I still do not object to these forks. Having been around the moto end of stuff long enough, I don't get worked up on account of dialing stuff in. For me these forks are no different.

So, our team weight is 370 ish plus camelbacks and helmets. We ride a lot of stupid drops, really tight trails, palmetto roots and sometimes hardpack ruts, plus lots of sand. Speeds range from crawling and plonking to decent flat ground cruising, and when possible, long descents like those at AORTA.

Neither of the two forks we currently own were great as delivered. They were ok and ridable but nothing to rival Ohlins. This past weekend had me spend some time working out some of the major concerns.

FWIW, I had previously modified a damper for easy consistent bleeds, so this chapter is closed.

Simple damping changes are made via fluid viscosity changes, and easy bleeds make this a no brainer, provided you not on the damper or your setup notes what fluid you installed. By now most of the world is familiar with Peter Verones fluid chart. This is a huge help when comparing fluids, whether for your tandem, single or motocross / harescramble ride.

Scroll down this page to compare fluids.

http://www.pvdwiki.com/index.php?title=Suspension_Fluid

Be forewarned that not all fluids have good lubrication properties. Many folks buy fluid based on its VI ratings. Typically, I have found that fluid with high VI's, tend to have less slippery feel on the sliding surfaces. Some fluids are just crap, and others are excellent. FWIW, for Silkolene Pro RSF is a great fluid in demanding apps, but is not good for being slippery. Guess what Fox now uses? Torco stuff works very well. Also, if the viscosity is proper my favorite is Mobil1 ATF, trust me it works very well and has for years in my KTM race bike.

My notes show that the ATC forks prefer heavier fluids to obtain damping. 20 weight Bel-Ray was on the shelf and has been used with good results. These dampers are very basic and use no amount of shim stacks like the more sophisticated counter parts. This doesn't make it bad, just different, and somewhat easier to get good settings. Those of us that have time on 70 and early 80 motocross machines rode on damper rod forks, these were simple in operation and maintenance, but performed very well in many bikes. Consider the 81 Maico 490, which still works well for non stadium type tracks. Shim type dampers are great if you have shims AND know how to make good shim changes. This is its own book and won't be discussed here.

Now to focus on the mechanics of the sliding tubes&#8230;

If you have time to work on your fork, I suggest you remove the wheel with the bike supported, remove the springs, and remove the damper rod nut and spring plunger nut, both of these are located in the forks outer tube lower fitting behind the axle. This will allow checking the tube movements with no outside force applied. Also, remove the four cap screws securing the fork brace.

In this setup, slide the forks telescopically, do they move freely? Don't let the damper foul you checks on the right side leg. If the forks feel notchy, loosen and remove the fork brace mount pinch bolts. Did the fork get better?

These were checks I made to our forks repeatedly until I was able to make the movement smooth.

To gain smoothness, these are the things I did to free up the forks and why.

I decided the fork brace mounts and triple clamp pinch bolts can not secure the tubes tightly without distorting the clamps to a shape that is no longer round and true. Basically, the pinch bolts begin to cant the clamp edge into the tube causing distortion. If you prevent the distortion with less torque on the bolts, slippage will occur. My remedy for this was to install NAS 43 DD spacers of the proper thickness in the gaps of the clamping surfaces. This allowed full torque on the fasteners with no distortion since the spacer was now holding the pinching surfaces parallel. I checked the clamps holding ability on the tubes to ensure no slippage. This included checks for twisting easily by hand force, and exerting bottoming forces by hand to see if the tubes slipped. These were also monitored during the first ride as a double check. FWIW, we did have tubes slip several times prior to this mod, and this was on account of not being able to get enough clamping pressure on the tube prior to the clamp distorting and going out of round.

In regards to the clamp up for the fork brace mounts, the ECDM was fine on the lower tubes external surface. The Fandango however, with spacers installed a very exact zero / zero slip fit. This would not work since the clamps would not hold the brace to tube tightly. I made shims for each clamping surface. These shims were nothing more than aluminum tape, cut 1" wide with scissors. The tape was wrapped and adhered one layer thick onto the outer tube, in the clamp location. The tapes split line was positioned 180 from the clamps pinch opening. The tape allowed excellent clamping of the mount to tube with full torque on the pinch bolts.

Next the tubes were checked for sliding action individually. Each tube was extended and compressed, checking for tight spots or poor quality in the movement. Fortunately, there was no additional work need for good movement.

I did check the lower bushings to ensure proper fit on the tube. To accomplish this, I ensured that the bushing ends where split had clearance, thus allowing the bushing to be seated onto the tube land 100%.

Prior to accomplishing a final install on the foot nuts for the damper and spring plunger, the damper was checked for smooth movement. Also, any travel adjustment were made. It was noted that the ECDM at full bottom out would have the dust seals hit the lower triple clamp with full uncushioned force. Not good. To prevent this, the bottoming cushion was extended by using a Thudbuster gray elastomer. This will give a more fluid bottoming control. I could have installed a rigid spacer but opted not to. The ECDM travel was maintained at slightly over 100mms while keeping Sherwoods spec for axle to crown.
In regards to the Fandango, I found I could increase travel, and removed some of the rigid bottoming spacers. Both bikes no longer run fork boots.

The foot nuts were final installed and secured.

The wheel was positioned and axle secured. What I have found works well for this when tightening the axle clamps is to install the capscrews part way. Then tighten the forward two capscrews on each leg until bottomed and snug. Then snug the rear pair on each leg. I then loosen the forward bolts ½ turn on each bolt. The rears are then made snug plus 1/8 turn. I then go back and tighten the four forward bolts ¼ turn. All are then rechecked, adding no more than 1/8 turn if needed.

Note also, that I prefer to push the fork tubes inward to ensure the hub is secure side to side, prior to any tightening of the axle clamps.

Focus then heads towards the triple clamps. I installed shorter NAS 43 DD spacers into the pinch slots of the clamps. Again, I ensured that each tube was clamped securely and the tubes were inspected for any slippage during the first ride. No slippagae was noted.

The sequence I use has me snug the upper clamp bolts with the tubes positioned for selected height above the clamps upper surface. You should never position the forks top cap with the caps sides in the clamping area. You should position the tube so the triple clamp is able to secure the fork cap and gain clamping support by clamping in the caps threaded area.

So I secure the upper clamp to tube joint first, these are snug plus a little bit. Next I snug the lower clamp to the tube. Again this is initially just snug. All of this assumes the headset is adjusted properly since any headset change will require this to be done again. Additionally, this is based on the triple clamps are not twisted on the steerer tube.

Go back and tighten all the triple clamp to tube bolts.

The final alignment and tightening involves the fork brace and it's clamps. I found it best to gradually bring these bolts to snug, then back off slightly. This allows the mounts to twist freely into proper position, and by having the brace float there is no spreading of drawing of the tubes inward or outward during this sequence. I gradually tighten the bolts, with a final tightening done once I know the brace nor clamps will slip out of alignment. Be careful if you do this since the brace mount pinch bolts have very few threads in the aluminum mount. I plan to use longer fasteners of the same length as the brace mount to prevent stripping the aluminum clamp.

This all sounds very complicated but is actually very easy to accomplish in a short time. Both of our forks move easily and fluidly. I run no seal saver fork boots, but this is your option. Experience for me has shown that unless they are cleaned faithfully, you will make sandpaper and grind up your forks finish.

Also, the grease I have been using is a low viscosity product from FORD. I was at the dealer get some parts for our toy hauler and saw this tube of grease. It's a plastic tube that screwed into my small bicycle grease gun. The grease is blue in color and contains Teflon. Cost was about $6 and for me close to home.

Cost for the spacers is low. One place listed them as a 10 piece minimum at 35 cents per spacer. I believe they also had a 25 dollar order minimum. For me these were stuff I have easy access to, so free for me.

So was it worth it. Absolutely!!!!!!!!! I personally like many traits of these ATC forks. I will admit that box stock they fall short. Not many will take the time and effort to make this happen, and I understand why. For us the fork works smooth enough now, with no notchy feeling, that the damper will need a more viscous fluid. The fork is also fully clamped with all the capscrews tight. I believe this added to the forks already rigid structure, but it may be something I want to believe.

Other things I hope to accomplish include&#8230;

Converting one fork (the Fandangos) to air sprung with external damping / possible lockout.

Locating anti-friction spring seats to minimize internal binding.

Anti friction the springs sliding surface against the tubes inner wall.

Will these forks stay or go, I'm not sure. My current lust is to convert the Fandango 29r to a Fox 36 / 20mm axle setup. As for the ECDM, I hope to buy a Kashima Fox 40 to install on the front. This is something for the future and may not happen, but time will tell.

PK


----------



## Hurricane Jeff (Jan 1, 2006)

I run a RockShox Boxxer on our Ventana El Testigo. The Boxxer is a dual crown fork with 20mm dropouts. My wife and I weigh 325lbs as a team.
I have also ran on our other tandems (another Ventana El Testigo we ran a Marzocchi Shiver, a Ventana El Conquisidor we ran a Hanebrink).
All the forks work great, although Ive been thinking of replacing the Boxxer with a Fox 40 DH fork, for really no apparent reason other that I really like how Fox forks perform on my single bikes, but the RS's are also really good forks...so it may be a wash.


----------



## ssulljm (Sep 3, 2006)

For my style of riding , Norcal dirt w lots of roots+ruts, I'm fully pleased w how my Softride stem w my original rigid fork performs.
My Bike:
http://www.oldmountainbikes.com/cgi-bin/bikes.cgi?bike=T136

Have tried forks on other tandems during group tandem outings, and if I was an extreme tandem descender, I'd consider one of the aforementioned moto forks. Climbing on my bike is a dream, and it never has to be locked out, as the stem functions beautifully w/o penalty of fork pogo.


----------



## drdoak (Feb 7, 2005)

PMK said:


> Have you posted a photo of this bike overall and maybe with some detail photos somewhere on the net? I would like to see some photos of it.
> 
> Thanks
> PK


I don't believe I've posted it before. Here is a link to the album. If you want more specific detailed pics, let me know and I'd be happy to post.

https://picasaweb.google.com/jeff.dambrun/VentanaECDM#


----------



## PMK (Oct 12, 2004)

Some detail photos of the NAS spacer installation. In the photos, you can see the spacers installed in the pinch area of the lower triple clamp, both left and right sides. Also the other photo shows the spacers installed on the fork brace mounting clamps. The Fandango fork required a shim of aluminum tape to obtain good clamp up of the fork brace clamp. On account of cables and hose, I didn't take photos of the upper triple clamps, they are however typical of the lower triple clamps.

The spacers allow the triple clamp pinch bolts to reach torque without the triple clamp distorting. The distortion would bind the clamps shape into the tube while placing the bolt at an angle with the head moved away from the tube.

We have a ride on the Fandango and tonight the ECDM. Both forks have freed up and have minimal stiction and move smoothly. Both forks triple clamps hold the upper tubes tightly with no slipping. Also the fork brace has not slipped.

The forks have improved enough that I now need to go into the damper and revalve the rebound to slow the extension. The fork action now has no deflection from binding, but rebounds too quickly. The fork will let the wheel follow the ground in compression, with no harshness felt in the bars. The rebound should be minor to cure and will allow me the chance to modify the cartridge body for better consistency.

The entire process may seem extreme, and yes I believe that these mods should not be needed. The fact is, many suspension assemblies and components, both Moto and MTB are production units that need work to get dialed in. As I already mentioned, it's very common to spend a lot of money or time testing and modding brand new suspension on motocross and woods bikes. By comparison, this has been very little time, easy to remedy, and the gains are more noticeable, cost for the parts if you had to purchase them is less than $10, assuming the vendor has no minimums.

Hope it helps if you own an ATC.

I wanted to add, that if you try this with washers instead of NAS spacers, be very careful of the outside diameter dimension. I initially mocked this up using AN960 series airframe washers. I was able to get them installed, however the washers outer edge contacted the fork tubes. Not sure if this would cause a concern or not but I didn't see it as a proper setup and changed it.

PK


----------



## Trails4Two (May 12, 2008)

*Thanks*

Great suspension write-up. It would actually make me consider an ATC again. Alex should hire you to "tune" the ones he gets new!


----------



## PMK (Oct 12, 2004)

Trails4Two said:


> Great suspension write-up. It would actually make me consider an ATC again. Alex should hire you to "tune" the ones he gets new!


FWIW, all suspension can use some personalized or team specific setting changes from oem. Some suspension components just require more than others.

As an example, the rear damper on my KTM 250 woods bike, is a hybrid I designed and built using parts from several different year dampers. The end result was the bike went from a machine with high speed compression spikes, and a rear damper that was a few mm's too long causing steering / handling issues, to a chassis that is easily dialed in and very ridable if it's not exactly perfect for the day.

The ATC on the Fandango will be super easy to get the valving correct. It's a hardtail, so there is no front to rear suspension balance to contend with. Just simple tracking, no deflection, compression and rebound.

The ECDM on the other hand will be a bit more to dial in. Tonight's ride had my wife / stoker understanding rebound damping. We (I) attempted to launch the machine and us by using a logpile as a jump. Nothing high nor steep. Normally we hit this feature around 20 mph. Prior to the fork work, the original RP3 had so little rebound she bounced up and the bike landed, if it even left the ground, nose low on the front wheel. The revalved RP3 works good and is a decent setup but not 100% when needed. With the DHX5.0, she gave good feedback, I instructed her to make certain clicker changes and we had a very balanced and fast setup with the non modified fork. The bike would cross the logpile, the opposite side would be a flat landing, totally uneventful, maybe we got air, but it was small if we did. Tonight's ride had the fork tracking very well, so our speed was up for the pedal effort. When we hit the logpile, the fork rebounded fast enough to have us almost bounce the front wheel over and did launch the bike, landing way too front wheel high. Suffice to say, I was interrogated immediately. I explained rebound damping of the fork and the merits of external adjusters, which led into the Kashima FOX 40 in black.

I'll revalve the ATC regardless. If I arrive at settings worth posting I'll share them.

The irony of this ATC stuff though is I'm starting to wonder if I am the only one riding them.

PK


----------



## TandemNut (Mar 12, 2004)

Trails4Two said:


> Great suspension write-up. It would actually make me consider an ATC again. Alex should hire you to "tune" the ones he gets new!


Should a product that's been produced as long as the ATC need this much tuning?


----------



## PMK (Oct 12, 2004)

TandemNut said:


> Should a product that's been produced as long as the ATC need this much tuning?


The obvious answer is no, and honestly, if damping tuning results involve much testing it's Fox40 for the ECDM, and ATC with spares for the Fandango or maybe a FOX36 converted to a 29r fork.

On the flip side though, the ATC is a torsionally rigid platform well suited for a tandem.

Sadly the ATC is somewhat dated by todays current damper designs, and the notchy action compounds this.

Then again, many of the current forks have smooth action but are prone to flex and even failure of internals on account of taking the lightest weight by design possible, or damper designs that are very sophisticated and not serviceable by most folks.

It would be great to see a torsional deflection vs force graph for the various forks. Then plug in a ride performance rating to see how everything stacks up.

I haven't given up on these ATC forks yet, if it does come around, it may find all the good traits of rigidity, travel, 29 or 26, and ease of maintenance to be envied. On the lacking end, it will need fluid changes for damping adjustment vs clickers on other brands. Not a bad tradeoff if you can find happiness in the damping and don't require lockout.

Ironically, I never expected the fork to get this good so easily. About 1 hour per fork so far, and with a good guess on fluid settings, another hour max. Cost has been negligible.

Time will tell.

PK


----------



## PMK (Oct 12, 2004)

Trails4Two said:


> Great suspension write-up. It would actually make me consider an ATC again. Alex should hire you to "tune" the ones he gets new!


Relating to your previous post regarding the idea of a 140mm fork, Marzocchis are typically a very easy conversion.

I have a double crown Drop Off I had planned to run on the Cannondale. At 170mm it was way to long, and yes a lot of travel compared to the 100mm Moto on it.

I forget the exact number I clipped it to, but if not right at 110mm something very close to it.

If done properly, changing travel from oem of 170mm to anything less and back are easily reversible mods.

PK


----------



## PMK (Oct 12, 2004)

8 more miles on the ECDM with the freed up ATC.

The fork is better, but it is becoming apparent that rear setup of our ECDM far exceeds the ability of the ATC fork.

I'll continue to improve these ATC forks I have, keeping updates posted here.

Over a week ago, I spoke with Alex. We discussed the ATC plus some other forks like the White Brothers 100t, the Groove USD series and even the Risse.

I would recommend, that unless you NEED a bargain double crown type fork, you will probably be better off to purchase one of the other forks he recommends. I know some folks run non approved tandem forks also, that's fine too in my book, (I know Alex is cringing with good reason) if you have your facts for what you are buying. I say this based on having a good idea of how much these forks will need to dial in and keep consistent from ride to ride.

Yes it is an easy fork to work on and maintain, but unless you want to take the time...you would likely rather be riding. For me, I am a suspension geek and have been working moto suspension and playing test rider since the mid 70's. Simple and easy in this situation may be a bit more than most folks care to play with.

I am by no means disappointed in the ATC, and suspect I'll get a dialed setup for the hardtail Fandango 29r. It will take some work, involving testing and some tuning but it should be doable. The hardtail rear end can not out perform the ATC like the ECDM does.

Time will tell what fork ultimately goes on the ECDM, but at the moment, the DHX 5.0 I installed on the rear dialed in real close to spot on with no big mods internally. Our greatest deviation from Foxes settings are running Pro Pedal threshold between clicks (non detent position). As I posted before, I am really leaning towards a modified Kashima FOX 40. Whatever route I take, I'll post the setup settings.

PK


----------



## Stevoo (Mar 9, 2007)

Marzocchi Jr. T. on Ellsworth. I limited the travel with internal spacers to 6". Using 15wt oil, played a bit with the damping, use the optional stiffest springs offered and bought seperately from Marzocchi, added air caps mostly to bleed off any accumulated pressure from time to time. No need to add air as the stiffer springs are just about right for my normal stoker. Adjusted the oil level down a bit to allow full stroke. Supple for the first part of the stroke, stiffens out well near the limit. Does eat the bumps well. The mods made it less bouncy and more confidence inspiring. Heavy steering feel. Has been a good fork for the job. No issues with seals and they are still going strong since new in 2002. As with any fork you can spend forever with the variables. You could make it a full time job just tuning forks and shocks. Certainly better than out of the box and no doubt I will continue to fiddle with it from time to time. I do like the fork. Lock out would be nice.


----------



## Trails4Two (May 12, 2008)

*Jr T modification?*

Stevoo,

Could you give more detail about your Jr T mod? I've got one at the original 170mm and would be very interested in lowering it to 150-160.


----------



## PMK (Oct 12, 2004)

In regards to the JrT's and Super T's, there are two different design platforms.

For model years 2002 and prior they utilized 30mm upper tubes, 2003 and after went with 32mm upper tubes.

By comparison, The WB 100's are 32mm uppers as are the USD type forks lowers.

As I mentioned, I have a 170mm Marzzochi clipped to about 110mm. Typically, the mod is very easy. You'll need a piece of 1/8" wall thickness aluminum tubing to loosely slip over the cartridge body. If you want a 130mm travel fork make a 40mm spacer sleeve for each leg. If the fork has coil springs, they can be replaced with shorter springs, or if a spacer lives on the main spring, trim it to offset the spacer added to limit extension.

For several years, and possibly still, Marzocchi was selling a second set of negative (top out) springs to shorten the forks from 130 to 100. This works, but can make the fork have a dead feel as opposed to being more lively at longer extensions.

If you have down time later in the year, or want to send it here and back sooner I'll make the mod for you.

Unfortunately I didn't take photos of the DO triple when I did it.

PK


----------



## PMK (Oct 12, 2004)

Is anyone else running an ATC fork that reads these forums? Before I spend more time writing I wanted to see if it is even worthwhile.

Our ECDM fork is what it is. Not bad but needs a revalve to get better. Sometimes notchy but mostly pretty smooth now.

Our ATC on the Fandango 29r has been less consistent. After this weekends ride with some new simple mods, it has been smoother than the ECDM fork, and consistent for the entire rides.

PK


----------



## giff07 (Jun 7, 2010)

I would be interested in more info on the Magic 100T. This is our second one on our ECDM and I find the newer one to be smoother, the break in was shorter and I run more air pressure than the one on our Fandango. We are a 360 # team. I would also like to hear about settings for the Fox RP3 rear shock but maybe that needs a whole different thread.
I am running 55# of air in the Magic after setting the IMV valve about 6 clicks from wide open and the rebound screw closed about 3/4 of a turn. I am still adjusting as the fork is still breaking in somewhat. I am much happier with the new version. The 100T we had on our Fandango I ran only 30# of air, 3 clicks from wide open on IMV and wide open on compression and would still come back with sore hands and shoulders.
On the RP3 I run 215# of air, rebound about 4 clicks, and we use pro pedal most of the time. 
I am still learning about suspension settings so please excuse any errors that are obvious.
Ed and Pat Gifford
Toms River, NJ


----------



## eischman (Apr 5, 2005)

I am sooooooooo happy with the DUC32 I bought off ebay and sent to maverick to tune up and setup for our weight and riding style. Last weekend we rode the SM100 and it was flawless. Although I do not have much to compare it to I am so impressed with this lighter weight triple clamp fork. The only problems we had was with the timing chain and rear wheel.


----------



## PMK (Oct 12, 2004)

Ed I can't help with the WB stuff at this time. We don't have one to test or even go through basic settings.

In regards to your RP3, when you run Pro Pedal, which PP setting. Our RP3 has the ability of selecting one of 3 settings.

Reference page 11 of this manual

http://www.foxracingshox.com/fox_tech_center/owners_manuals/06_RearShock_en.pdf

Position 1 was way to soft and no amount of air pressure would take the marshmallow feel away.

We tested in full PP but never rode while set there excepting dead smooth road sections, and even then, for us I believe the bike was faster not in #3.

All our riding was done via PP2. This gave a decent compromise. Our settings were 225/230 PSI with a small can and team weight of about 370 plus gear.

Besides revalving the RP3 for better rebound, now able to run 4 clicks out from full slow, I have made a conversion to the internal floating piston filler, so now it is more reliable and adjustable in pressure easily and without special tools. This can alter the internal progression of pressure, similar to, but not as extreme as on a DHX5.0 air.

Consider also, that on many forks and rear dampers, that adjustments to the rebound can alter compression flows too as many rebounds are not checkplated and freebleed in two directions. As rebounds are opened or closed, this alters the pressure values inside the damper to unseat the compression shim stacks and can change the way the bike feels in some situations.

PK


----------



## giff07 (Jun 7, 2010)

Hi Paul,
We usually run PP3 and full suspension switching between the two as the conditions dictate. I also have been flirting with the idea of finding a PP2 setting that works for most conditions we ride. Sometimes my stoker becomes pre occupied with switching the settings and forgets about the other aspects of the ride.


----------



## giff07 (Jun 7, 2010)

Hi Paul,
We usually run PP3 and full suspension switching between the two as the conditions dictate. I also have been flirting with the idea of finding a PP2 setting that works for most conditions we ride. Sometimes my stoker becomes pre occupied with switching the settings and forgets about the other aspects of the ride.
Ed


----------



## PMK (Oct 12, 2004)

Ride a bit in PP2, make minor (1 click) changes to the rebound. Go firmer, ride a bit, go 2 clicks softer ride a bit. Work this until optimized.

While testing try and ride sections that are all similar, or the same sections repeated. Don't let the stoker make a change until you have forced yourself to ride the entire section (unless dangerously wrong). Before making the change ask what she noticed, liked and didn't like.

Once set, I doubt you'll need PP1 for anything except the moon, PP2 should be your home setting with PP3 for flats. 

With PP2 setup, the bike will bob some but if the air pressure is correct, it should be minimal, and give good results.

Rebound set full closed or open is bad. Since the RP's don't use a rebound needle all settings can be used effectively, however, the shape of the ports does not have the same net change from one click to another. Best rebound settings are #3 thru #6.

PK


----------



## Okayfine (Sep 7, 2010)

*Marz 66SL*

1. What fork make/model and what frame make/model?

2006 Marz 66SL. This is the air version, no springs. Oil damping. On an '06 ECdM.

1a. single or dual crown
Single

1b. lock out?
No

1c. axle type 20mm thru? 9mm QR?
20mm through axle. Before Marz switched to a QR 20mm axle.

2. Team weight?
Probably 380ish with gear and water

3. Type of riding.
Everything this side of drops and jumps. Fireroad, singletrack, rutted singletrack, dry creek crossings, sections of boulder downhill.

4. Any feedback regarding performance, maintenance etc. (positive or negative).

Aside from the poor Marz owner's manual (one manual per model year, despite the vast number of different forks produced for that year, makes it very difficult to figure out which acronyms apply). Worse that there were a half-dozen 66 models produced, so it took quite a bit of time to find the correct service manual.

Use has been great, so far as my knowledge goes. I run the positive air at ~145lb, negative at ~40. Have come close to using all the travel a handful of times, but most it sags about 20% and I use another 40% when riding, according to the stanchion zip tie. Has provided a stable platform when we hit rough stuff. Probably a bit tall for our needs.

Maintenance isn't difficult. Again with the task of finding the correct service manual. I did fill the oil to the specified amounts (200ml in left, 50 in right), but came away with a very harsh top-out. Another 50ml in the right leg cured that. Otherwise a seal kit and a couple hours did the job. Not as easy as the RP3, but, hey...

On RP3 notes, we use ~170lb in the can with ProPedal set on. I tried to get my stoker to play with some of the settings to figure out what she likes and likes better, but that never got very far. Via the witness ring, we use up about 85% of travel at that pressure.


----------



## Okayfine (Sep 7, 2010)

Borrowed from the "New ECdM Build Advice" thread, TandemNut said:



TandemNut said:


> Second the Marzocchi option for single crown, but team weight has a bearing on that as well; typically teams over 300lbs are better suited to double-crown forks.


So, given that our team weight is ~360lb with gear and we ride hard enough to go through three WI rear hubs and crack the ECdM frame, is there a more definite weight limit for an '06 Marz 66SL? I did not detect any damage/fatigue when the fork was out during the rebuild and I don't want to be surprised by it on the trail.


----------



## PMK (Oct 12, 2004)

Okayfine said:


> Borrowed from the "New ECdM Build Advice" thread, TandemNut said:
> 
> So, given that our team weight is ~360lb with gear and we ride hard enough to go through three WI rear hubs and crack the ECdM frame, is there a more definite weight limit for an '06 Marz 66SL? I did not detect any damage/fatigue when the fork was out during the rebuild and I don't want to be surprised by it on the trail.


Most modern large tube forks are pretty well built structurally. Most times it's not going to be a catastrophic structural failure but rather cyclic stress type failure. Pretty much a situation of how many times can you bend the beer can before it breaks, not so much a John Belushi smashing the beer can on his head Ala "Animal House".

Best to do visual inspections at higher stress locations like the crown, bridge, axle mounts, and lower legs about half way between the seal and axle.

Should you plan to find something, NO. Could you find something, Yes.

In regards to single crown vs double, the obvious advantage is much less flex loads into the double crown. Aside from that, the lowers and bridge see the same, and possibly more stress in some cases than a single crown. One other big consideration to loads induced into the forks is extended length. It can be nice to have lots of travel, but with it comes added torsional and front to rear flex.

We don't ride a single crown fork on our tandems. I'm pretty confident we could on our XC Fandango, but the ATC is now working very well so it will stay. As for the ECDM, where and what we ride I would not have faith in a single crown lasting very long. If it ever gets here, a Fox40 Kashima is going to replace the ATC not on account of flex or lacking structural strength, we just need better damping control.

PK


----------



## giff07 (Jun 7, 2010)

Hi Paul,
We have been fooling around with the rear shock adjustments under various conditions for the last week trying to find the acceptable set up for PP2. Amazingly we seemed to have settled on just about the same as yours even though I tried a lot of different things with air pressure and rebound. We currently run 230 # air pressure and 5 clicks from open on PP2 and the bike handles well under all but the most exteme conditions and my stoker is comfortable and happy. Yesterday we did a 30 mile ride on a canal path ( think rail trail) as a test for PP3. It felt very reminiscent of our Fandango hardtail but more comfy over any ruts or bumps. Smooth and fast. The only time we had any bobbing problems was in standing and that is more of a technique issue rather than a suspension issue.
Ed


----------



## PMK (Oct 12, 2004)

Ed, 

Glad to hear you have tested a bit to find better settings. Your setup runs similar to ours, but most important is it is pretty much up the middle on the rebound clicker. The nice thing about being dialed on PP2 is the bike has a wider terrain envelope and can inspire more confidence as you carry momentum and more speed through sections.

PP1, is very soft on compression damping. It will be cushy for anyone that rides it, provided there is enough air pressure to hold the back end up on rolling bumps. With PP1 selected the terrain envelope is good for roots and rocks when the bike / team does not carry much momentum across those features. In my opinion the setting is marshmallow soft and the rear end wallows constantly for us. It is especially unnerving in fast corners as the rear end is bobbing and constantly changing the headtube angle and steering feel + inputs. I work harder in PP1 and we go slower, also the stoker doesn't like it blowing through the stroke and wacking pedals. If we still ran an RP series damper, PP1 would be our mud setting, slower speeds, softer damping to keep the rear wheel compliant over super slippery stuff, or hooked up in low grip conditions.

PP2 when setup well, will provide enough spring rate (psi) and firm the damping. Some times firmer damping can cause deflection issues on roots and rocks. The PP2 setting for us would unload the damper (blowoff) on extreme hits, but gave a good balance for rolling terrain and the high speed compression stuff like rocks and roots. Like almost all suspended vehicles, often times firmer damping, provides the control needed to ride rough sections at greater speeds and with more control.

The secondary benefit of PP2, is this setting should be pretty good for all but the smoothest terrain. Plus PP2 will save your frame from being pounded to death via lockout on rough terrain.

As for PP3, we only will run a full lockout on pavement or dirt roads. 

With us now running a DHX5.0 air, the version we have is clicker adjustable PP amounts. For us this works well, and let's the compression settings be better optimized, rebound also.

I spoke with Sherwood recently about something unrelated. The DHX damper was brought up. As he indicated, and I agree fully long before the conversation, sometimes having more features can make finding optimum settings more difficult. The DHX has been a good mod for us. Unfortunately it is not a plug and play swap. The air can volume is not optimized for the linkage rates of the ECDM and does not work well for us in regards to spring rate progression. Once this was settled, the air spring pressure was optimized, followed easily by rebound. The PP settings were a bit of a learning curve for Jeanne. The best method to optimize the back is to force the stoker to make changes and learn about how the bike reacts differently with each change. Even with an RP damper, move the rebound, to full open then full closed several minutes later. Then go back to center. Ride that for a short bit and open it a couple of clicks, then go back past center and run it with more rebound.

Eventually, the stoker should be able to find a setting that does not bounce her off the saddle, but is fast enough rebound that the captain retains lighter steering inputs and the bike turns consistently and predictable.

Dialing in clickers and oil levels (in forks), plus ensuring you have the proper springs can be a huge difference in how a bike feels and rides.

Glad you got it sorted out. Should be a faster safer bike to ride, and that is a good thing for you, maybe not others.

PK


----------



## PMK (Oct 12, 2004)

As noted in the ECDM topic, our current fork is a Fox 40 Kashima.

We are running the firmest spring (red) with the travel set to 5 1/2".

The good about the fork is how tunable and it's ability to work very well on all terrain.

The downside is the obvious stupid expensive cost.

The other downside was Fox as a company and their lack of getting the gold Kashima tubes close to the same color when they built it. We have one darker gold tube and one lighter gold tube. When asked about it, they said they are all this way, which is obviously not true.

The only way they would even consider, but not promising a matched tube set, was to send it in for warranty and wait.

If you consider this fork, be aware that you will need a different brake adapter for the caliper. The 203mm disc uses a smaller adapter, not uncommon but just worth noting when you order your fork. We went to Avid BB7's and I believe I had to install a 160 front adapter. No big deal.

Additionally, I plan to buy another axle if they are reasonable. When transporting in the van, I use a Hurricane fork up on a BikeTight platform. The Hurricane adapter is a loose fit to the axle and the bike rocks back and forth. Regardless, I either need to line the ForkUp with a plastic tube to prevent axle wear or have one axle for transporting.

If you have an old school Manitou 5mm super long allen wrench, dig it out. These work great for removing and installing the front wheel.

Performance wise, the added shortening spacers increase the preload on the spring to a proper amount for us at 355 plus gear. The spring rate is decent. 

Damping wise, the fork has adjustments for low speed compression, high speed compression, and rebound. With no shimstack changes the fork dialed in via the clickers.

One other motorcycle carryover used in the Fox 40 is bottoming control. I have not opened this fork, but if memory is correct it uses a bottoming cone type setup to gradually slow the fork as it reaches full stroke. We have ridden it and seen the "O"ring witness band pushed to 100%, but I can not recall feeling the bottoming in the bars.

As I noted in the other topic, this fork is very capable and lends itself to making a rider very confident, it lets you ride faster while safer, but when you miss a good line, you are going a good clip headed off course.

We like it and don't have any plans to make further changes.

Like so many things, not tandem rated but could be something to consider.

PK


----------



## Okayfine (Sep 7, 2010)

PMK said:


> Additionally, I plan to buy another axle if they are reasonable. When transporting in the van, I use a Hurricane fork up on a BikeTight platform. The Hurricane adapter is a loose fit to the axle and the bike rocks back and forth. Regardless, I either need to line the ForkUp with a plastic tube to prevent axle wear or have one axle for transporting.


This is interesting. I made a 20mm "Fork Up" type mount, but used 3/4" black pipe (from Home Depot, for gas work) and it is slightly too big in ID for the axle...so it wobbles during transport! I kept thinking about buying a legit item (but thinking $50 was highway robbery), thinking it'd be a perfect fit. Good to know.

I've used a piece of Teflon sheet (had some extra from an old project) to line the inside. Still wobbled a bit, but the axle was protected.


----------



## DHMASTER (Oct 12, 2010)

*Fox 40*

Fox 40 with their heaviest spring, Bicycle Fabrications Tandem 8" travel F&R.
Riders weigh 380lbs +70lb bike.
Downhill riding, resort and trail, jumps, drops, high speed.
Fox makes some stout products, the heavy spring nicely matches the 700lb DHX 5.0 spring in the rear, all the travel has been used but no hard bottom out..... yet.


----------



## PMK (Oct 12, 2004)

I was curious and went looking for Bicycle Fabrications and found their website.

The 70lb bike spec had me wondering why. This bike is in some photos on their website. Definitely a rugged race bike, all steel US made machine.

Here's a photo from the websites photo section

http://www.bicyclefabrications.com/Bicycle_Fabrications/__FS_special_P.html#3

Very nice, though a bit overkill for XC riding.

I may steal your idea of multiple steering lock cushions, very good idea.

PK


----------



## reamer41 (Mar 26, 2007)

Trails4Two said:


> Stevoo,
> 
> Could you give more detail about your Jr T mod? I've got one at the original 170mm and would be very interested in lowering it to 150-160.


Trails4Two, did you ever get the info you needed for your fork mod?

I've got a Jr T shortened to 130mm. Easy! I spoke with the folks at Marz and they seemed confused when I said I wanted to buy a kit for shortening the fork.
"Just cut a spacer to the length you want." He recommended plastic (PVC or ABS?), but the pipe I bought was too large, so I ended up cutting a 40mm piece of of an old handlebar.

I seem to recall placing the spacer above the top-out spring. It's been a few years. Let me know if you have questions.


----------



## Trails4Two (May 12, 2008)

*Jr T mod*

Did the spacer addition change the spring rate (make it stiffer)? It's not that critical since I did a pretty big handlebar/stem swap to get some weight off my hands, and in so doing happened to get the fork dialed in really well. We are really happy with it even in full travel right now. For an inexpensive fork it really eats up everything we throw at it.


----------



## reamer41 (Mar 26, 2007)

Trails4Two said:


> Did the spacer addition change the spring rate (make it stiffer)? It's not that critical since I did a pretty big handlebar/stem swap to get some weight off my hands, and in so doing happened to get the fork dialed in really well. We are really happy with it even in full travel right now. For an inexpensive fork it really eats up everything we throw at it.


Good point. As I said it had ben a while. There is a preload spacer above the spring which is about 60mm stock. It can be shortened or replaced to suit. I replaced mine, ultimately increasing spring preload by about 20mm. It can be challenging to replace the topcap if there is too much preload.

So you've got a more upright riding position on your bike? There is a guy in Phoenix that had his tandem set up that way....You like it? Pictures?


----------



## reamer41 (Mar 26, 2007)

1. What fork make/model and what frame make/model?
Marz Jr T @130mm (orig 170) Stiffest springs w/air caps
Ventana ECDM 2006

1a. single or dual crown
Dual Crown

1b. lock out?
No

1c. axle type 20mm thru? 9mm QR?
20mm. I would not go back to 9mm on a mtb tandem.

2. Team weight?
350lbs, was 375-380 (capt lost weight)

3. Type of riding.
Singletrack, often rocky

4. Any feedback regarding performance, maintenance etc. (positive or negative).
Not nearly as stiff in terms of steering and deflection on old ZZYYX or ATC, but very smooth in terms of bump compliance. I run around 20psi in each leg, but initial travel is still a little too soft. I've gone to 10wt oil (from 7) and I will try heavier still next time I'm tinkering. Also less steering lock compared to ATC.

No maintenance issues. One seal may be leaking a little after 4 years. Not bad.


----------



## PMK (Oct 12, 2004)

FWIW, when shortening forks, consider also the volume in the air chamber is decreased.

If you run the same amount of fluid, either by measuring volume in cc or ml, or doing a dimensional check on a fully bled fork, you will lose spring rate of the air spring on account of it not building 40mm of travel pressure.

So, if you shorten a wet fork, to regain bottoming resistance, which most shortened forks will need, plan on adding some fluid.

PK


----------



## PMK (Oct 12, 2004)

reamer41 said:


> 1. What fork make/model and what frame make/model?
> Marz Jr T @130mm (orig 170) Stiffest springs w/air caps
> Ventana ECDM 2006
> .


What year is the JrT? More importantly, what are the tube diameters, 30mm or 32mm?

The 2mm is a large percentage change in cross section and stiffness provided they did not try to retain flew for a better ride quality.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> FWIW, when shortening forks, consider also the volume in the air chamber is decreased.
> 
> If you run the same amount of fluid, either by measuring volume in cc or ml, or doing a dimensional check on a fully bled fork, you will lose spring rate of the air spring on account of it not building 40mm of travel pressure.
> 
> ...


Hmmm. I had increased fluid volume somewhat. I don't remember exactly how much, and I'm not at home now.
Anyway, I had recently been condidering reducing fluid and increasing air pressure as I havent been noticing bottoming (but have been using the full stroke) and have been blowing through the initial stroke very easily. My thinking, however flawed, was that by gaining a larger air volume and increasing pressure I would get a stiffer spring rate that is more linear.

From your initial comment, I'm thinking I was off base here... Thoughts?


----------



## reamer41 (Mar 26, 2007)

PMK said:


> What year is the JrT? More importantly, what are the tube diameters, 30mm or 32mm?
> 
> The 2mm is a large percentage change in cross section and stiffness provided they did not try to retain flew for a better ride quality.
> 
> PK


I don't know. I bought the fork from Alex in 2006, but I don't know the model year.
I've never measured and I'm a couple thousand miles from home. I'll measure when I get home. From looking at the Marz website, I'm thinking it's a 2006 w/32mm tubes.


----------



## PMK (Oct 12, 2004)

reamer41 said:


> Hmmm. I had increased fluid volume somewhat. I don't remember exactly how much, and I'm not at home now.
> Anyway, I had recently been condidering reducing fluid and increasing air pressure as I havent been noticing bottoming (but have been using the full stroke) and have been blowing through the initial stroke very easily. My thinking, however flawed, was that by gaining a larger air volume and increasing pressure I would get a stiffer spring rate that is more linear.
> 
> From your initial comment, I'm thinking I was off base here... Thoughts?


Not to avoid a direct answer, but there is not enough information to give good feedback.

Typically, springs support and damping controls.

The key here is are you blowing through the stroke, or need more preload and mid stroke support.

Additionally, is the fork harsh in any way on small square edge bumps. If not, I would add compression damping first, if it's underdamped, no amount of spring will keep it riding proper.

Increasing viscosity will also add to the high speed rebound which will keep the front wheel more planted.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> Not to avoid a direct answer, but there is not enough information to give good feedback.
> 
> Typically, springs support and damping controls.
> 
> ...


The fork is not harsh at all. I have felt it is under damped, and I will try a more viscous oil. I've already gone from 7.5 to 10. Any recommendation on brand and/or weight of oil?


----------



## PMK (Oct 12, 2004)

reamer41 said:


> The fork is not harsh at all. I have felt it is under damped, and I will try a more viscous oil. I've already gone from 7.5 to 10. Any recommendation on brand and/or weight of oil?


What brand and spec is the oil you had and went to?

The easiest way to know if your change was good our bad is to compare the fluid on PVD's wikki chart.

http://www.pvdwiki.com/index.php?title=Suspension_Fluid

Use the viscosity of cSt (centistokes) @40 degrees C.

Also, find fluids for your fork with lower VI ratings, typically they have better "slippery" performance which is good for an open fork.

If you have any cartridge type forks, or are rebuilding a rear damper, look for higher VI rated fluids since the rear damper works much harder than the forks.

For a tandem with a simple rebound tune only fork I wouldn't be hesitant to look at stuff in the 20 wt range, 60 ish on cSt.

You asked for a recomendation, even though this is not a 20wt, it has decent numbers.
Motorex racing fork oil 15wt, 69.80 cSt @ 40C and a 160 VI. If you have a local CycleGear, motorcycle accessory shop, they may stock it, I have seen them carry Motorex fluids before.

Don't be afraid to accurately work the fluid level to gain a firmer mid travel spring rate AND to minimize fork dive and bottoming.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> What brand and spec is the oil you had and went to?
> 
> The easiest way to know if your change was good our bad is to compare the fluid on PVD's wikki chart.
> 
> ...


Ah, I had been looking at PVD's site even before you posted it. Lots of information there. Who would have thought that the "weight" of oil changes from one brand to another. Is motor oil similarly varied, I wonder?

OK. So I'm back home. Answers to questions asked. I do have 32mm fork tubes. The last batch of fork oil I used is Bel-Ray High Performance fork oil 10W. From the PVD table that shows a cSt of 33.5, which looks to be in the right direction from the stock of 26.1. There is a cycle gear shop near by. I'll see if they are carrying the Motrex 15wt and give it a try.



PMK said:


> Don't be afraid to accurately work the fluid level to gain a firmer mid travel spring rate AND to minimize fork dive and bottoming.
> PK


Well, I won't be afraid to do that, I'm just not sure that I know what I'm doing. 

Thanks for your help, PMD. I'll update with results.


----------



## reamer41 (Mar 26, 2007)

Cycle Gear didn't have the Motrex, but had Maxima 20wt ([email protected] 65.60), which has similar numbers on the PVD chart. So I gave that a try. What a difference!

Fork felt much more stable when cornering on relatively smooth trail, but harsh over bumps. Even small rocks were a little jarring. Also, even when set up with too much sag we never used the last inch of travel -- even off a 18" drop. I felt it quite difficult to control the bike on a rocky downhill.

When draining the old fluid I was reminded that I had previously lowered the fluid volume to regain the last inch of shock stroke. Maybe I had taken it too low, but the recommended 265cc seems to be too much. I am using air-caps and have been using about 20psi to get about 1.25" sag.

I will try reducing fluid volume a little bit at a time, but the harshness felt on rocky trails leads me to believe that something between the Bel-Ray 10wt and the Maxima 20wt might be the ticket.


----------



## PMK (Oct 12, 2004)

Take a photo of the fork caps.

I would not, unless I had no other means use a volume amount for how much oil. The best way is to overfill and suck out the excess.

You ensure the cartridge is bled 1005 by cycling the damper rod, then fully compress the fork. Use a syringe with a hose, or an old spray bottle. Mark the depth and remove the excess fluid.

You should realy think any change through on an air sprung fork. 

Consider if you had to much fluid, it will not use full travel. If you lower the pressure the fork gets harsh.

Run the most preload or air pressure to support the front that gives good small bump compliance, then retain that pressure while decreasing the oil level.

The reality check is that you need to balance small bump compliance, mid stroke support (for good handling) and bottoming.

BTW, Maxima is good stuff too. Testing with the same brand and dropping a viscosity may dial it in as you mentioned. The problem may be the cartridge is not capable of the load.

I have a Marzocchi Drop Off Triple I never installed. Shortened the travel, and so on. It is a very basic fork, but one I know will handle the damping loads with no issue. The simplicity and non cartridge design are what will let it work.

The is a fine balance on a cartridge setup where you must retain enough cartridge pressure for the fork to function, but still unload enough hydraulic pressure to prevent harshness.

PK


----------



## PMK (Oct 12, 2004)

Also,if I get a chance, I'll post some video we got this weekend. Pretty graphis of just how much punishment these bikes take when riding them.

It may give you some ideas on tuning the fork.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> Take a photo of the fork caps.
> 
> I would not, unless I had no other means use a volume amount for how much oil. The best way is to overfill and suck out the excess.
> 
> ...


Thanks for your response. It leave me with a couple questions: The Marzocchi manual gives fluid in CCs. You are saying better to measure the level, right? I am assuming (always dangerous) that you would measure from the top of the tube with fork compressed and springs removed. That right? I guess it doesn't matter as long as you do it the same way each time. How do you establish the starting fluid level? 
265CCs doesn't leave much air-volume when the forks are fully compressed.

You wrote:_Consider if you had to much fluid, it will not use full travel. If you lower the pressure the fork gets harsh._

I think I may not have been clear in my post above. The fork was harsh all the time, with 20psi and still harsh with only 10psi. I reduced the pressure to see if we would use more travel, not due to harshness. But still we did not use the last inch.

With these air caps it is hard to preload the coil springs. Considering I'm using air pressure should I, and how much should I, preload the springs? It is a little tricky to thread these non adjustable caps on while holding down a bunch of spring pressure.

Here are the caps, and for good measure the springs...


----------



## PMK (Oct 12, 2004)

That's what I wondered, similar to my Drop Off Triple, except I have single springs.

So now tell me because I don't want to confuse your fork with others, where is the rebound clicker, internal or external, photo of that and have you adjusted it to make the fork react better?

PK


----------



## PMK (Oct 12, 2004)

You are correct, fully bleed any cartridge device by cycling the damper shaft. Fully bottom out the fork. No springs, damper rods fully plunged if applicable.

Set your depth tool for however many mm of fluid. Suck it to that level.

By using a simple spray bottle, remove the bottle, remove the little filter screen if it has one, use masking tape to indicate the depth. Slide the tube into the fork and while maintaining the set depth, pump and spray the excess fluid into the bottle. If the fork has been cleaned and this is it's first reset, you might even spray it into the container.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> That's what I wondered, similar to my Drop Off Triple, except I have single springs.
> 
> So now tell me because I don't want to confuse your fork with others, where is the rebound clicker, internal or external, photo of that and have you adjusted it to make the fork react better?
> 
> PK


Since changing oil I haven't had a chance to do anything.

The rebound adjuster is at the bottom of the right leg. 6 turns, no clicks, from full open to full closed. Even with the 20wt, It seemed about right at about 1 or 2 turns back from full closed (from slow rebound).

The left leg is spring only. No adjuster and, I think no damper rod.

At one point I was running the air assist on the left leg (with reduced oil) and the spring preload adjuster on the right leg with the recommended 265cc oil. It worked OK, but at some point I switched back to air in both sides.


----------



## PMK (Oct 12, 2004)

I know this is the back end, I have another video showing it in square edge type terrain.

This is Santos Spider Kingdom trail head west towards Landbridge.

If you look close you see the tire sliding and kicking up stuff.






This is what your fork has to keep up with.

PK


----------



## PMK (Oct 12, 2004)

reamer41 said:


> Since changing oil I haven't had a chance to do anything.
> 
> The rebound adjuster is at the bottom of the right leg. 6 turns, no clicks, from full open to full closed. Even with the 20wt, It seemed about right at about 1 or 2 turns back from full closed (from slow rebound).
> 
> ...


This is what I wondered, the manual link, if it is correct is for a non rebound damping adjustable fork. This type fork is pretty basic damper rod design, mainly relying on freebleed holes (orifices) to control the damping.

Per the Marz webpage archive, the damper has an SSV, problem is it's not tunable.

I don't have magic settings for you. To optimize the fork will take a little effort, but once done you'll be able to repeat or tune from a good base point.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> This is what I wondered, the manual link, if it is correct is for a non rebound damping adjustable fork. This type fork is pretty basic damper rod design, mainly relying on freebleed holes (orifices) to control the damping.
> 
> Per the Marz webpage archive, the damper has an SSV, problem is it's not tunable.
> 
> ...


Yeah, I forgot that the manual show that there is no adjuster. There is. The right leg has a knob on the bottom -- see picture. I don't know what's up with the manual -- otherwise it seems to be the same fork. Next time I have the fork apart I'll take pics of the damper rod. The first 3-4 turns of the damper adjustment seem to have no effect on rebound, but from 4 to 5 and 5 to 6 the effect is very noticeable. 
For part of the first ride with the new 20wt oil I had the damper adjusted 5 turns from full open and that may have contributed to harshness -- it may have been packing down at that setting.

I pumped some of the 20wt out of the fork today. With springs removed and the fork compressed there was about 75mm from fluid to top of the tube. I took a guess, and fluid level is now 120mm from top. Stoker not available, but I did a solo test ride over some junk (bricks, 4x4s, etc...) I put in the road. The fork seems less harsh and is using more travel. Test ride tomorrow if I don't have to go to work.


----------



## reamer41 (Mar 26, 2007)

PMK said:


> I know this is the back end, I have another video showing it in square edge type terrain.
> 
> This is Santos Spider Kingdom trail head west towards Landbridge.
> 
> ...


Cool video! the shock sure moves a lot! The trails around here are rocky and rough. Maybe I'll rig a camera for similar footage.

After I get the fork worked out I'll be looking for advice on optimizing the shock!

the fifth video here: http://www.bikeradar.com/news/article/bikeradars-top-5-videos-of-2010-28735 reminded me of your footage with the rear-facing camera.


----------



## StanleyJ (Dec 11, 2010)

Everyone who's posted seems to be on 26er tandems... so what's hot and what's not as far as 29er tandems go? I want to avoid White Brothers & Maverick if only for the fact I'm in Hong Kong and should anything happen, getting them serviced will be a major PITA.

The tandem team would actually be fairly light (<290lbs) but trails around this part of the world would want about 5in/120mm of travel. As much as I like Fox forks, their 29er stuff has too little travel and a 15mm axle would probably be too wimpy? Marzocchi 29er forks seem too XC as well (15mm axle again). Magura still don't have a 29er fork. So single crown wise it looks like it'd have to be a RockShox or a Manitou Minute/Tower (once that's released, with its tapered steerer) 29er?

A Manitou Dorado Pro would obviously (obviously?) seem to be up to the task...though even as a 29er fork, it's got bucketloads of travel at 175mm... how difficult would it be to reduce it to a more sensible 130mm~150mm?

*Forgot about the Manitou Tower 29er fork...


----------



## PMK (Oct 12, 2004)

StanleyJ said:


> Everyone who's posted seems to be on 26er tandems... so what's hot and what's not as far as 29er tandems go? I want to avoid White Brothers & Maverick if only for the fact I'm in Hong Kong and should anything happen, getting them serviced will be a major PITA.
> 
> The tandem team would actually be fairly light (<290lbs) but trails around this part of the world would want about 5in/120mm of travel. As much as I like Fox forks, their 29er stuff has too little travel and a 15mm axle would probably be too wimpy? Marzocchi 29er forks seem too XC as well (15mm axle again). Magura still don't have a 29er fork. So single crown wise it looks like it'd have to be a RockShox or a Manitou Minute/Tower (once that's released, with its tapered steerer) 29er?
> 
> ...


I'll get clobbered for saying it but we run an ATC on our 29r Fandango hardtail and find it a good match for the bike, my stoker and I, plus the terrain we ride.

With some simple details as I posted here our fork is easily up to the task and we have no plans to swap it.

But...if you plan to run a 29r full suspension tandem, the fork will work decent, but may hold you back on serious terrain.

As far as simplicity, this fork is as simple as an old school Manitou EFC.

PK


----------



## reamer41 (Mar 26, 2007)

reamer41 said:


> I pumped some of the 20wt out of the fork today. ......fluid level is now 120mm from top. Stoker not available, but I did a solo test ride over some junk (bricks, 4x4s, etc...) I put in the road. The fork seems less harsh and is using more travel. Test ride tomorrow if I don't have to go to work.


We got out for a ride yesterday. The fork was much better with the lower fluid level. 
Sag @ 1.25 inches (out of 5 total) 20psi air static air pressure.

The fork felt good over everything except a rocky, twisty downhill piece. On that trail it was still not confidence inspiting. Too much compression dampening. Less so then with the 10wt oil. Everywhere else the 20wt seemed an improvement.

I'll try the 15wt, and see how that is.

Stupid question: If there is no damper in the left leg, no need to change that fluid, right?


----------



## PMK (Oct 12, 2004)

Correct on the non damper side provided you don't change fluid level.

Try 15wt, if that doesn't get it we can talk about making the fork more position sensitive.

PK


----------



## reamer41 (Mar 26, 2007)

All Right! I drained the 20wt on the right leg and replaced w/Maxima 15wt. Filled to 125mm from the top (previously 120mm, also dropped left leg to 125mm from top). We got a ride in yesterday and I think that this is a pretty good setup.

The fork is still very compliant over small stuff, but doesn't blow through the travel easily, yet uses pretty much full travel on the big hits. Rocky , twisty, downhill felt as good as it's going to get I guess. 

I will do some experimenting with the rebound knob--last ride was at 4 turns (of 6) from full-open.

Thanks for all your help and suggestions, PK.


----------



## PMK (Oct 12, 2004)

reamer41 said:


> All Right! I drained the 20wt on the right leg and replaced w/Maxima 15wt. Filled to 125mm from the top (previously 120mm, also dropped left leg to 125mm from top). We got a ride in yesterday and I think that this is a pretty good setup.
> 
> The fork is still very compliant over small stuff, but doesn't blow through the travel easily, yet uses pretty much full travel on the big hits. Rocky , twisty, downhill felt as good as it's going to get I guess.
> 
> ...


Your welcome.

If you need more performance from it, let me know before you pull it apart next time. I'll have you measure a couple of things and see how that compares to how it doesn't meet your requirements.

PK

Wanted to add that with a non check valve design freebleed, the rebound adjustments will also, to some degree effect low speed compression damping. Faster rebound will soften the compression and firmer rebound will firm the compression. Most often not a problem, but still something to consider.


----------



## reamer41 (Mar 26, 2007)

Seeing PMK's video of his rear shock in action inspired me to follow thru on videoing front and rear suspension action of the EDCM. Over all I'm pretty happy with how the fork is working. I think I'll I'll work on some fine-tuning, maybe either slightly increasing air pressure or raising fluid level slightly.

Here's a link to the fork in action.


----------



## PMK (Oct 12, 2004)

reamer41 said:


> Seeing PMK's video of his rear shock in action inspired me to follow thru on videoing front and rear suspension action of the EDCM. Over all I'm pretty happy with how the fork is working. I think I'll I'll work on some fine-tuning, maybe either slightly increasing air pressure or raising fluid level slightly.
> 
> Here's a link to the fork in action.


For grins, could you measure from the bottom edge of the lower triple clamp to the top of the fork tube.

I ask from seeing how much rubes are set above the upper clamp.

There are some critical dimensions regarding this but also it can play into where the fork is truly settled in the stroke.

The bottom out, while severe is not bad, it is "G"out followed by a step up. The most difficult terrain item for a tandem on a flowing trail in my opinion.

With both springs removed, will the fork bottom on the internal bottoming cone or are the seals hitting the bottom of the lower triple clamp? Reference the manual link you posted, pages 9,10. They mention the notch in the tube and max headtube stuff.

I'm suspecting the fork is too long and causing some of the concerns.. but the forks action looked pretty good.

PK


----------



## reamer41 (Mar 26, 2007)

PMK said:


> For grins, could you measure from the bottom edge of the lower triple clamp to the top of the fork tube.
> 
> I ask from seeing how much rubes are set above the upper clamp.
> 
> ...


There is 137mm from the top of the lowers to the bottom triple clamp. (I had thought I had shortened to 130....its growing!?)

Marzocchi was good enough to put "Min" and "Max" marking on the tubes for the lower triple clamp, and I am honoring the "Min" mark. With the springs out and the fork bottomed there is very little free space between the lower and the clamp, but they don't touch.

There is about 145mm between the upper and lower clamps.

I'll start a new thread for the video of the rear shock. The back end is performing less well.


----------



## reamer41 (Mar 26, 2007)

Paul,

A quick question for you: We were out the other day on one of our local oft ridden trails. On one section of rough descent the fork bottomed hard, with a bang, where it usually doesn't. It was hard! For a moment I worried about structural failure, or something. It seemed OK for the rest of the ride and there is no external evidence of anything wrong.

Could that type thing be caused by too low oil level? Previous bumps stirred things up and left me with no compression damping? Whatever its cause, it was very unsettling!

--Charlie


----------



## PMK (Oct 12, 2004)

Bringing this back to the top for some added stuff.

#1 If you run a Fox fork or any brand that has fluid for the lower tubes isolated from the damping fluid (closed cartridge forks), keep the lower fork lube replenished. This can be a big factor in how the fork feels to the rider and how it follows terrain.


#2 Curious how many tandems still have ATC forks, and if so, is there an interest into some simple and inexpensive mods to up the performance. Some of the items have already been posted, but this past week I converted our Fandango fork to a "wet" fork. No more greasing. I made some other mods, so individual mods can not be evaluated. IMHO the fork is another step up from where it was. If no one is running these forks I won't bother.

#3 Those teams attending AORTA 2011, are there any specific fork or shock issues we need to focus the informal suspension discussion about? The discussion will be geared towards setup. I'm asking in case I need to pillage a manufacturers site for cutaways or other specific details I may not have committed to memory.

PK


----------



## giff07 (Jun 7, 2010)

Hi Paul,
Anything with the WB Magic 100 T and the Fox RP23 would be helpful. I know you don't own the WB fork but it is probably the fork that Alex sells the most of. From setup, tuning, modification and service for both of those.:thumbsup: 
Ed Gifford
the Snot Rocket tandem


----------



## Rida29r (May 26, 2009)

I guess we're the only Fox Vanilla fork out there?


----------



## PMK (Oct 12, 2004)

I need to ask again about the ATC fork, is there any interest in them?

I know others run them having seen two at AORTA 2011. Not sure if the fork warrants the work in other folks eyes.

I am tempted to have some good springs wound to save weight and get better action from the fork. I don't really want to go it alone but may.

Any interest or stick a fork in 'em, they're done.

PK


----------



## Team Fubar Rider (Sep 3, 2003)

Hey PMK,

Who do you (or have you ever) used for a custom wound fork spring? I was thinking I would like to get a touch stiffer spring for our tandem since we're running the firmest available.

Thanks!


----------



## PMK (Oct 12, 2004)

Rida29r said:


> I guess we're the only Fox Vanilla fork out there?


From doing homework on your profile...seems to indicate Ellsworth Witness.

There are a few Vanilla versions over the years, I'm optimistic you are running a 36 version.

Should be fine, though technically not an "approved" tandem fork. Depending upon the payload weight and how crazy the stoker allows the captain to be will sort out not only its durability but also if additional efforts need to go into tuning it.

I'd guess you at least got the travel shortened to something to allow the bike to steer, and firmed up the spring to keep your toes on your feet.

Being serious, how does it work for you two, what is the setup, and if it's not so good, why?

PK


----------



## PMK (Oct 12, 2004)

Team Fubar Rider said:


> Hey PMK,
> 
> Who do you (or have you ever) used for a custom wound fork spring? I was thinking I would like to get a touch stiffer spring for our tandem since we're running the firmest available.
> 
> Thanks!


I have spoken with Cannonracecraft. You will need to know your criteria for them to wind to. Mainly OD, Free Length, Minimum Length, and Rate. Also if the ends are special that may need to be noted.

http://www.cannonracecraft.com/

My last discussion with them was a tapered profile small diameter heavy spring for a Moto fork on our Cannondale. I never had them wind it as I stuffed old Judy bumpers that were cut to a smaller OD in the lathe, down the inside Dia of the spring.

That worked real good for adding rate and progression.

Your other option, and I constantly research what I have on hand plus catalogs is to find a spring to set inside the original spring, but with the wind in the opposite direction.

PK


----------



## Okayfine (Sep 7, 2010)

Hello Paul and all,

We have a 2006 Marz 66SL (dual air). I've noticed recently that the negative chamber has been leaking pressure over short periods of time and when disconnecting the pump from the mini Shrader port there is an abnormal spray of fork oil (it is minor as to amount, but six months ago and prior there had been none).

Research on MTBR and other sources has indicated two o-rings that are known to fail over time and would present as the oil-intruding-into-the-negative-pressure-resevoir issue. However, Marz USA does not have any o-rings available, nor do they have the left-leg cartridge available.

With lower/no negative pressure the fork is much more active than prior. I don't know the long-term consequences of running with low/no neg pressure, or if it is such that a new fork should be on the horizon.

There are a few 66's out there - anyone have experience?

Thanks


----------



## PMK (Oct 12, 2004)

Okayfine said:


> Hello Paul and all,
> 
> We have a 2006 Marz 66SL (dual air). I've noticed recently that the negative chamber has been leaking pressure over short periods of time and when disconnecting the pump from the mini Shrader port there is an abnormal spray of fork oil (it is minor as to amount, but six months ago and prior there had been none).
> 
> ...


Bummer about the fork. I own a Marzocchi on my Turner and it has the similar setup with negative and positive air chambers.

You've no doubt read what could be found. Somewhat of a common problem. Some say just dis-assemble, clean, service and ride.

It probably should get new seals.

As for riding without negative air, it will be a long fork and my tend to top out a lot more,. I don't know if there is a bumper also inside it to prevent damage.

As for a new fork, much of that is how worn and scratched the upper legs are. If you can be comfortable taking it apart, the "O"rings can be matched up at a hydraulic shop, worse case is ordering some from McMaster or other supplier.

Sorry I can't offer more, I see you are also planning a trip. Makes sending it here or elsewhere tough.

PK


----------



## Okayfine (Sep 7, 2010)

We rode it yesterday. A somewhat unpleasant experience due to the topping-out as you indicated. There doesn't seem to be a bumper, given the mechanical clacking which at times was semi-violent. There was also more sticktion, which follows given what Marz says in their service manual regarding the negative air chamber's function. It may have also been a function of the increase positive air I put in to compensate for the soggyness, so there is a bit of experimentation.

I can change the oil and seals and I'll see what the o-rings look like - have to make some soft jaws to hold the cartridge shaft. I never found specs for ID or thickness/OD, and the Marz guy didn't have any. My experience in the automotive world, a little excess thickness means things don't fit any more.

Thanks, Paul!


----------



## Okayfine (Sep 7, 2010)

An update - I am now in possession of 99 each of the round profile and the square profile o-rings used in the Marz 66SL Doppio cartridges. Had to buy in batches of 100. I pulled the Doppio apart and exchanged the o-rings. Used parts didn't look noticably worn. 

However, the new parts are holding pressure and not pulling in oil. 

I went ahead and changed out the oil seals since I had a spare set and it was more or less time. Which then presented a new problem of not holding positive pressure. Seems the genuine Marz seals are slightly undersize - they needed almost no pressure to install, and leak (alternatively) air or oil. I have another set of Enduro seals coming in the post as I keep one set on hand...but ended up digging out the "old" seals from the trash and reinstalling them - they required more pressure to install than the "new" ones. Hoping for positive pressure so we can ride this weekend. Enduro seals won't be in until Wednesday.

On the flip side, I'm pretty quick R&Ring the fork seals and cartridges...:madman:


----------



## PMK (Oct 12, 2004)

Some forks are better than others in regards to working on them. Some are easy to destroy while others can easily be repaired. Having 99 extra "O"rings could be an indicator of your need to work on your machine more often...

Often the worst part about bicycle suspension work, especially in regards to air forks, is worn anodized surfaces coupled with lack of frequent normal maintenance and planned obsolescence or no availability of parts.

If I had a fraction of the money spent replacing stuff I was unable to repair due to maintenance neglect, I could possibly buy another ECDM or Fandango.

Some of the most neglected areas are removing the forks lower legs and cleaning all the dust from the seal area. No amount of washing or external maintenance will accomplish this. Also, the degradation in how the fork feels is often huge. So not only is the fork being destroyed, the ride is poor and control on rough terrain is reduced. Often this results in a complete fork replacement.

PK


----------



## Okayfine (Sep 7, 2010)

We ride in a pretty dusty environment, but there wasn't much grit intrusion past the wipers. The felt seals even seemed reusable. I typically clean the bike, at most, after every second ride, so that may have something to do with it. And, while dusty, we don't deal much with wet conditions.

If anyone has an '06 Marz 66 (or whatever other years/models use the same) and needs the Doppio o-rings, PM me for my address and send me a SASE.


----------



## PMK (Oct 12, 2004)

The comment about the fine dust getting past the dust wiper was not directed towards you in particular, more a general statement letting everyone understand more about this and possible consequences.

Running parallel to this are items like the RP3 and all similar type rear shocks.

PK


----------



## Okayfine (Sep 7, 2010)

Updating for new fork. Changed out from an '06 Marz 66SL air to a 2011 Marz 66EVO coil. Main changes are 38mm stanchions (up from 35), QR20 (up from bolt-on through-axle), 8" disc post mount (up from 6"), and the differences between air spring and coil spring.

Had it out on the trail today and it is a nice fork. Stiffer than the '06, mainly felt when climbing square hits at an angle. Plusher, but that may be my higher-than-spec'ed air pressures in the '06. No sticktion from new, and that QR20 is really nice. And, despite the advertised 180mm travel, I seem to have more standover than I did with the '06 which was 170mm travel. I didn't measure A-to-C, but I should to see if there are differences to account for the added standover. Not complaining! All in all, a worthwhile upgrade for the pittance I paid from Huck'n'Roll.

Still working on settings, but currently has 15psi preload, about 2/3rds coil spring preload, 6 of 8 clicks toward hard compression dampening, and middle-of-the-road rebound settings. The preloads probably won't change much, but the rebound/compression are sure to.


----------



## PMK (Oct 12, 2004)

Side shot please.

FWIW, I typically run the cable or hose inside the fork leg and ensure the hose does not touch the upper tube.

Overall though sounds good.

PK


----------



## Okayfine (Sep 7, 2010)

The brake line is free from the stanchion by about 1/2" and this doesn't seem to change under compression. The Hope lines are rubber-coated braided stainless, so there'd have to be a fair amount of rub before there'd be damage. Marz's front-mount clip is alright, but their older rear-mount clip (as on my '06) was better. Luckily I didn't have to reposition the line coming out of the caliper, but it was close.

Not sure where I get the added standover. A-to-C on the '06 is ~22", while A-to-C on the '11 appears to be closer to 22.5". Very odd.


----------



## reamer41 (Mar 26, 2007)

I've run my hoses both inside and outside. I also prefer inside. From that front-clip it cleanly route inside the leg. I figure it's less susceptible to damage -- not that I've damaged brake hoses...


----------



## Internal14 (Jan 21, 2004)

How about the new Fox Talas 34 in 29er dress. Tapered Headtube. 

Any feelings?


----------



## PMK (Oct 12, 2004)

Internal14 said:


> How about the new Fox Talas 34 in 29er dress. Tapered Headtube.
> 
> Any feelings?


On what frame and how small are the riders?

PK


----------



## ds2199 (Sep 16, 2008)

Internal14 said:


> How about the new Fox Talas 34 in 29er dress. Tapered Headtube.
> 
> Any feelings?


We are currently riding this setup on out new ECDM 29er. We are a light(ish) team at around 270lbs. So far so good, I like the fork. We did not get the opportunity to get many miles in before the snow.

I'll update in the spring/summer when we get some more time on it. For what its worth, we don't launch any big drops...


----------



## PMK (Oct 12, 2004)

ds2199 said:


> We are currently riding this setup on out new ECDM 29er. We are a light(ish) team at around 270lbs. So far so good, I like the fork. We did not get the opportunity to get many miles in before the snow.
> 
> I'll update in the spring/summer when we get some more time on it. For what its worth, we don't launch any big drops...


Exactly, so much of this fork to use discussion is based around the size of the riders, the ability of the riders, the terrain, how much the riders want to push the extremes of where they ride, and for some cost / warranty concerns, others often prefer "tandem rated" endorsements from the manufacturer, some prefer performance over endorsements.

You just need to find the category that fits and go with it.

We run two different brands of off-road forks on our tandems. One is not tandem rated, but works very well. The other is not a popular fork because the performance is poor as it comes from the manufacturer. I was just lucky and sorted it out, making it our hardtail fork for the Fandango 29r. Would we be happy with a White Brothers, maybe, a Marzocchi, maybe, a Maverick, you see my point.

The flip side is, if you are a shop, and you install say a Fox fork, that is explicitly not approved for a tandem, are you as the shop owner willing to take that risk?

So many decisions...

PK


----------



## She&I (Jan 4, 2010)

What's not working...

White Brothers Magic T100 leaks all air out in <24 hours. Any idiot checks before I ship it to MRP? Works fine while there's air in it. Thanks for any advice.

Mike


----------



## PMK (Oct 12, 2004)

She&I said:


> What's not working...
> 
> White Brothers Magic T100 leaks all air out in <24 hours. Any idiot checks before I ship it to MRP? Works fine while there's air in it. Thanks for any advice.
> 
> Mike


Valve core tight...top cap tight (snug)

PK


----------



## PMK (Oct 12, 2004)

Internal14 said:


> How about the new Fox Talas 34 in 29er dress. Tapered Headtube.
> 
> Any feelings?


Guess now we know, funny title for your post

http://forums.mtbr.com/ventana/follow-along-children-tandem-build-763755.html


----------



## Trails4Two (May 12, 2008)

She&I said:


> Any idiot checks before I ship it to MRP?


Valve core: sometimes tiny things can get stuck in the core itself. Pull it , clean it and try again. You can also test by dripping water on it (while at full pressure) and looking for bubbles.


----------



## She&I (Jan 4, 2010)

Thanks, guys. Will do.

Mike


----------



## giff07 (Jun 7, 2010)

Also with the valve core, check the cap. We had a very small piece of debris stuck inside the cap/cover and it was placed so it was bleeding air from the fork. Drove me crazy.
FWIW, our Magic fork seems to lose air during the coldest time of the year. Spoke to WB about it and they felt it was something that was pretty normal since it held air when it was warmer.
Ed and Pat Gifford
the Snot Rocket tandem


----------



## She&I (Jan 4, 2010)

I removed and cleaned the valve core, and so far it looks like we're back in biz. No apparent leakage in 20+ hours.

PK, T4T, Giff: Thanks greatly for the info. You guys saved me some hassle, not to mention down time.

:thumbsup::thumbsup::thumbsup:

Mike


----------



## powermac (Mar 8, 2009)

Iam selling my cannondale moto fr fork in perfect condition.

eighty aid serviced, red and blue spring + tool, powder coated in dark blue, reeinforced for disc brake use, only 100km since last full service

if you need more information send me a pm

shipping from germany to other countrys is available

anyone interested?

powermac


----------



## PMK (Oct 12, 2004)

powermac said:


> Iam selling my cannondale moto fr fork in perfect condition.
> 
> eighty aid serviced, red and blue spring + tool, powder coated in dark blue, reeinforced for disc brake use, only 100km since last full service
> 
> ...


What bike or tandem did was it removed from? What fork was installed to replace it?

FWIW, you may need to list this in the MTBR classifieds to prevent both yours and my post from being removed.

PK


----------



## powermac (Mar 8, 2009)

Hi,

the fork was removed from a germans cycles tandem, i will replace it with a rigid fork because the last 3 years i rode both forks time by time and for my use of the bike the rigid is the better choice (speedy forest way and empty road tracks). Most of this time the moto fr lies around. You can see the tandem on the german cycles website in the gallery. I know about the classifieds but the problem is i dont have the number of posts for it, i think this will change soon 

Power


----------



## CaptainHaddock (Mar 3, 2012)

So on the topic of Suspension forks, has anyone converted a cannondale road frame by way of attaching a suspension fork up front and riding as a hard-tail? If not, any suggestions there in?


----------



## Trails4Two (May 12, 2008)

*Conversion*

Just my .02 but I wouldn't do it. Try riding your bike cyclocross style, then if you like roads and trails and want more - buy an actual off-road tandem. Used C'dale, Fandango, or other.


----------



## CaptainHaddock (Mar 3, 2012)

Trails4Two said:


> Just my .02 but I wouldn't do it. Try riding your bike cyclocross style, then if you like roads and trails and want more - buy an actual off-road tandem. Used C'dale, Fandango, or other.


As a practical matter, I agree with you and my wife would never let me try such a surgery (at least not this early in the game). We have tested the bike out as a cross and it works quite well, but I'm having fun looking at my various options!


----------



## PMK (Oct 12, 2004)

Eye Captain, how intense them trails be you plan to navigate. Could be some rough sailing for that road frame.

I would really be more worried about the low ground clearance on the RT2, plus the uncertainty of if there is enough strength in the frame for the stress of off-road and added length of the fork. Purely speculating, but economically the cost of the proper bike vs ER visit.

You do realize that you can sell an RT2 for easily what you can buy two used Cannondale mountain tandems for, provided the RT2 is not trashed.

PK


----------



## CaptainHaddock (Mar 3, 2012)

PMK said:


> Eye Captain, how intense them trails be you plan to navigate. Could be some rough sailing for that road frame.
> 
> I would really be more worried about the low ground clearance on the RT2, plus the uncertainty of if there is enough strength in the frame for the stress of off-road and added length of the fork. Purely speculating, but economically the cost of the proper bike vs ER visit.
> 
> ...


Practically speaking, they would be very mild trails, as I don't think my wife would take kindly to technical single-track. I only just got her bike communing two years ago, and she is still gun-shy of much other than road riding. I've taken her & the tandem up the leif erickson trail here in Portland and she's responded mostly positively there.

The plan (in my mind) is to ride the RT2 for two years or so, and then upgrade to a touring frame w/ S&S for air-transport. Somwhere in that two years, I'm hoping to get my hands on a late model cannondale MT series. (irony here is that my dad had the very MT I want, but he sold it long before I met my wife)

That being said, aside from bashing in a tube on rocks, in theory it should be durable enough to put a fork on and take it on the trails around these parts. Back in the mid-90's, Bianchi made a triple butted steel mtn. frame that their teams raced with some success (or at least I don't remember hearing anything about the frames folding during rides).


----------



## [email protected] (Jun 28, 2011)

We are currently running a Fox Float 36mm (single crown) with Lock Out and 20mm thru axle on our Ellsworth Witness. Our team weight is only about 235, but we ride it pretty hard. I've lowered the travel to 130mm using the internal spacers.

Over the years I've tried the Maverick DUC and the White Brothers 100T - and this latest Fox fork blows them both away in terms of great handling, stiffness, and ride quality. Yes, Fox won't officially say its OK to run this fork on a tandem - but don't let that stop you. It's stronger than both the Maverick and the White Brothers.

have some friends that just got a 29er Ventana built with the Fox Float 34 and it's definitely the only way to go with a 29er tandem these days. So much better than the White Brothers fork - and according to Fox the 34mm legs with tapered steer tube is nearly as stiff in every way as the 36mm with straight 1 1/8" steer tube. Nice to finally have awesome forks for the awesome tandem mtn frames that have been around for several years now!


----------



## ds2199 (Sep 16, 2008)

[email protected] said:


> have some friends that just got a 29er Ventana built with the Fox Float 34 and it's definitely the only way to go with a 29er tandem these days. So much better than the White Brothers fork - and according to Fox the 34mm legs with tapered steer tube is nearly as stiff in every way as the 36mm with straight 1 1/8" steer tube. Nice to finally have awesome forks for the awesome tandem mtn frames that have been around for several years now!


We are are also running a Fox 34 (actually a TALAS not FLoat) on our new ECDM 29. It is still too early to report, but base on the handful of rides that we have on it, I'd say that I prefer it to the Maveick Duc 32 that we have on our Fandango 29. More to come once we get some serious miles on it. I will say that we are big fans of the new bike too!! :thumbsup:


----------



## PMK (Oct 12, 2004)

[email protected] said:


> We are currently running a Fox Float 36mm (single crown) with Lock Out and 20mm thru axle on our Ellsworth Witness. Our team weight is only about 235, but we ride it pretty hard. I've lowered the travel to 130mm using the internal spacers.
> 
> Over the years I've tried the Maverick DUC and the White Brothers 100T - and this latest Fox fork blows them both away in terms of great handling, stiffness, and ride quality. Yes, Fox won't officially say its OK to run this fork on a tandem - but don't let that stop you. It's stronger than both the Maverick and the White Brothers.
> 
> have some friends that just got a 29er Ventana built with the Fox Float 34 and it's definitely the only way to go with a 29er tandem these days. So much better than the White Brothers fork - and according to Fox the 34mm legs with tapered steer tube is nearly as stiff in every way as the 36mm with straight 1 1/8" steer tube. Nice to finally have awesome forks for the awesome tandem mtn frames that have been around for several years now!


Smaller, lighter teams can get away with a lot more. At 235 pounds, that's less than many single riders. You Ellsworth is likely on 12 pounds more than the single bikes these folks ride also.

Ironically, knowing the Ellsworth is 26", the fork that will outperform that Fox 36 is the Fox 40. The one advantage gained from a single crown vs a dual crown is turning radius. There is a weight difference, but the offset is strength and steering precision.

29r fork, on a hardtail like a Fandango or Cannondale, having a Fox 40 as a comparison, the modified ATC gets the job done. The ATC would improve another step if I spent the money on lighter spring(s).

BTW, my #2 29r pick would be a modified Fox 40 or Fox 36.

PK


----------



## patineto (Oct 28, 2005)

I'm currently running a JP Morgen stem but I'm thinking of trying one of my 888RC forks on this GT tandem, Yes I will need to restrict the travel and get stiffer springs for it.









Any advice on the 888's to much fork...??

JP stems are works of art and they also work really well, specially on bikes like tandem's.


----------



## clj2289 (Jan 2, 2010)

Any thoughts on this fork?

Manitou Suspension Forks & Bicycle Components for Mountain Bikes


----------



## PMK (Oct 12, 2004)

CLJ, I / we have never owned, ridden or worked on one. For single bikes they get great critiques overall for earlier model years. Some of the older froks had problems and also these older forks existed in a time less "good" for Manitou.

I did some searching for more info, this link gives some better details.

Manitou Dorado Pro MTB Fork Review | Mountain Bike Blog || SINGLETRACKS.COM

FWIW, my one personal reason against these forks are that they are a USD (upside down) style fork. Granted they can work very well, and done properly can be very flex free. The issue I have and see constantly with MX stuff is that the internal oil is always resting upon the seals, and these style forks are more prone to fork seal leaks. Not saying this will or will not happen, just is typical of the USD design.

Saying that, if we had the need and those forks were fit the bill, we would likely run them.

Supposedly, they are handbuilt in the US, arrive in a Gun Case for a shipping box, and have one year of included maintenance. So basically about as "works" as you can get off the shelf in a bicycle fork.

Before you pull the trigger, ask the pinnacle question...are they longer in length than your current WB 100 fork? If so how much will it alter the bikes handling and standover.

PK


----------



## TandemNut (Mar 12, 2004)

clj2289 said:


> Any thoughts on this fork?
> 
> Manitou Suspension Forks & Bicycle Components for Mountain Bikes


I've got a brand new reduced travel one here if you want it. Very plush, but too plush for our team weight.


----------



## clj2289 (Jan 2, 2010)

Paul,

Thanks for the info. I will have to consider all of that. 

Alex, I will have to give you a call and chat about that fork, but I thinking that if its too plush for you guys, then it might be too plush for us as well. You have provided us wonderful support with us on our White Bros and I really appreciate that. 

I'm thinking about considering one of the Fox 34 29er forks. Not sure which one, but now that folks have spent some time on them, it might be a good time to get folks to come forward with their field test experiences.

Cheers,
Chris


----------



## Rmabus (Jun 12, 2012)

*Fork help*

So I have been reading about the different options you guys are talking about, but my needs are a little different.

I converted a burley zydeco to more of a mountain bike setup. I will be riding mostly tight hard pack single track in north texas. I am using this with my kids so our team weight will be about 250. I don't want to kick the front end up to much but would love to run a fork. Any ideas on what might work? PS. I would run a softride stem but I will be running a 100 mill stem so I am not sure a suspension stem will be short enough.


----------



## PMK (Oct 12, 2004)

Rmabus said:


> So I have been reading about the different options you guys are talking about, but my needs are a little different.
> 
> I converted a burley zydeco to more of a mountain bike setup. I will be riding mostly tight hard pack single track in north texas. I am using this with my kids so our team weight will be about 250. I don't want to kick the front end up to much but would love to run a fork. Any ideas on what might work? PS. I would run a softride stem but I will be running a 100 mill stem so I am not sure a suspension stem will be short enough.


Assuming the frame is a 1 1/8 headtube, your best bet is looking for a good condition used Marzocchi Dirt Jumper or similar series with the brake posts and quick release axle. This may be a tough request from what others have mentioned.

If the frame is 1", I doubt there is much left anymore.

Best of luck with it.

PK


----------



## Rmabus (Jun 12, 2012)

It is definitely a 1 1/8th. I talked to the owner of mtbtandem.com and he really kindof steered me away from a fork altogether, and recommended that I use this tandem as a test platform to see if I like it, then upgrade to a REAL Mtb tandem. My only issue is the fact that I am only going to ride this thing for about 3 years or so with my sons. As they get older they need to ride there own bikes. In other words I am not a long term tandem owner and dumping a lot of money into this or a better tandem is just not wise. I figure a used fork and maybe a front disk brake are about all I plan to put into this thing.


----------



## Okayfine (Sep 7, 2010)

Rmabus said:


> My only issue is the fact that I am only going to ride this thing for about 3 years or so with my sons


Big fat front tire? Don't know how fat a tire you can get away with, but I remember our old KHS off-road tandem came with anemic 1.9s. We run 2.5" WTB Dissents on our Ventana. Will depend on what sort of fork clearance you have, and the size of the rims...

Adding front disc requires the requisite fork and disc brake setup, but also a new hub (and likely a new front wheel build).


----------



## Rmabus (Jun 12, 2012)

I am thinking about simply leaving it alone. I am currently running a meat cleaver of a front Schwalbe tire. It is either a 2.25 or a 2.5. I will probably be going to a set of magura hydro rim brakes and leave it be.


----------



## Rmabus (Jun 12, 2012)

I have yet to take this off road as my kids wanted to ride there own new bikes first but spinning around the neightborhood even with the a 2.5 tire up front, I get the feeling I am going to be pulling for a dirt jumper fork soon. Anyone ever tried to drop the travel some to lower the crown height to accomodate a non sus fork frame?


----------



## Trails4Two (May 12, 2008)

*Dirt Jumper*

The DJ series is a spring fork with Air assist. If you don't put air in it, it will ride at about 75-80mm travel. If you find you are bottoming out, gradually add air and I would bet that you would soon be using full travel with no notable steering effects.


----------



## Rmabus (Jun 12, 2012)

You know I am thinking about this more but to be honest I am wrestling with how to go about getting this all done. I live in Dallas right so it is not like I need some serious duel piston disk brakes. The rear end is not even set for disk. So I have been kicking around the idea of a v-brake dj fork or the other duel crown tandem fork and using some magura hydro rim brakes for the short run. I don't want to put a ton of money into this yet so I am trying to work on the cheap. I know everyone says eventually you will spend more but the "time value" of money is also in play here.


----------



## Trails4Two (May 12, 2008)

*Fork*

A friend of mine in Denver just inherited a Cannondale Moto fork from a friend. It is 100mm travel, has rim posts and disc mount. It is a solid fork, we rode one for years. Others can add their .25, but it would be a good place to start. Price would probably be VERY low ( I can't speak for him directly. If you are interested post here. He is on the tandem forum or I can connect you.


----------



## Rmabus (Jun 12, 2012)

Trails4two. Pm sent.


----------



## OCFRED (Oct 20, 2012)

Wow, that's an old ass fork; personally I've been pleased with the RS Tora line since it uses a steel steerer and butted chromo stanchtions with 20mm maxle light lowers. Standard QR's flex awfully and aluminum unlike steel breaks before bending, got one on E-bay for around 2 bills and works well; make sure to get an air spring though.


----------



## DonP. (Dec 4, 2012)

*Fox Talas 36 RC*

How does the Fox Talas 36 RC hold up as a tandem fork? We are a 280lb team.


----------



## PMK (Oct 12, 2004)

DonP. said:


> How does the Fox Talas 36 RC hold up as a tandem fork? We are a 280lb team.


First off, understand that none of the FOX fork products are rated for tandems. Saying that though, a lot of people run them.

The 36 Talas you have should have more than enough knobs and adjustments to dial it in and provide excellent performance.

I'm not sure if yours is the RC or RC2 style cartridge. Not a big deal, but what is very worthwhile is the high speed compression clicker.

You will want to build the required routine maintenance tools and frequently change the lower fluid. This is very important since when accomplishing this task, you are cleaning the seals and lubing them.

Also, it is not uncommon to have the forks lowers crack at the axle perch. This caused by using a 5mm hex wrench that easily overtightens the pinch bolts.

I made up, (and recently lost, left in the bed of the Tacoma and drove away) a 5mm hex wrench on a screwdriver handle. This is easily capable of the 19inlb torque for the pinch bolts and axle. Also, after each ride, I always loosen the axle pinch bolts and axle itself to help prevent cracking.

We run a fork with similar features, a Fox 40 Kashima DH fork. It is really nice to have the ability to adjust easily for whatever the conditions are. Our recent FTF we attended had different terrain than home. Home is more sandy and rooted vs the FTF which is hardpack and rooted plus rocks. On our first ride of the FTF, after about a mile I had the stoker reach down and soften the DHX 5.0air rear shock Propedal which is basically the HSC. Once the back settled in and was hooked up well without harshness, I made a couple of changes to the front forks HSC. Without stopping or even slowing, we had the bike dialed in within 1/2 a mile.

Your RP23 on the rear is not as versatile, but the fork should be.

PK


----------



## XDEADGOATX (Jul 12, 2010)

*i am very interested if not sold yet...*

very interested in this fork please let me know if not sold...


Trails4Two said:


> A friend of mine in Denver just inherited a Cannondale Moto fork from a friend. It is 100mm travel, has rim posts and disc mount. It is a solid fork, we rode one for years. Others can add their .25, but it would be a good place to start. Price would probably be VERY low ( I can't speak for him directly. If you are interested post here. He is on the tandem forum or I can connect you.


----------



## ds2199 (Sep 16, 2008)

XDEADGOATX said:


> very interested in this fork please let me know if not sold...


I'll ask the guy if he still has it.


----------



## DonP. (Dec 4, 2012)

*Air pressure*



PMK said:


> First off, understand that none of the FOX fork products are rated for tandems. Saying that though, a lot of people run them.
> 
> The 36 Talas you have should have more than enough knobs and adjustments to dial it in and provide excellent performance.
> 
> ...


Received the bike yesterday and in checking things out found the fork is the RC2 model with the flip levers to secure the thru axel. The fork had 150psi and the shock was at 240psi. Seems high for our weight, I run 50/150 on my Enduro. What would you reccommend for starting pressures. We won't be taking any big hits for a while just light trail rides for now...


----------



## PMK (Oct 12, 2004)

DonP. said:


> Received the bike yesterday and in checking things out found the fork is the RC2 model with the flip levers to secure the thru axel. The fork had 150psi and the shock was at 240psi. Seems high for our weight, I run 50/150 on my Enduro. What would you reccommend for starting pressures. We won't be taking any big hits for a while just light trail rides for now...


240 in the rear RP23 may be a few PSI high, I don't know which version of the shock you have. This can effect the pressure and setup. Can you post a photo? As a good guide, set the base pressure for the point of stoker alone and just enough pressure for zero sag. Note the amount and if needed add in 10 psi increments until both riders gives about 3/8" sag.

The fork and 150, well, that is a matter of accomplishing some static tests for sag. Aim for less than 20%. You will probably need to work the pressure until the fork / steering feels good.

PK


----------



## PMK (Oct 12, 2004)

Don P, just saw the photos, you have a large can rear shock, that forces you to run higher pressures to minimize wallow in the mid stroke.

PK


----------



## Okayfine (Sep 7, 2010)

We have the same shock and run it at ~175psi. Stoker weight of ~135, team weight of 340+gear. Lots of variables, but I'd think 240psi is high.


----------



## PMK (Oct 12, 2004)

Okayfine said:


> We have the same shock and run it at ~175psi. Stoker weight of ~135, team weight of 340+gear. Lots of variables, but I'd think 240psi is high.


So much depends upon stoker weight. I forgot OK do you have a small can shock or large can shock? We have run both and from experience know that WE need more pressure (about 25 psi increase) if we run a large can shock.

The reason why is progression of the air spring. The large can has a flatter rising rate. This makes for a softer mid stroke with the bike settling lower. For us, this is bad since it corners vaguely and "drags" cranks or tubes at bad times.

If you run a super long fork this can help but tends to make it chopperish with a long fork and low rear.

In the end though, each team is different, and on tandems more than singles it is not always as easy to just carry across the numbers.

I'm certain if 10 teams rode our ECDM, some would not like the ergos, some not like the tires, and without doubt, many would probably not like our suspension settings. Change the settings and what was hated a moment before may be nirvana.

PK


----------



## Okayfine (Sep 7, 2010)

We decided we're running the big can, '11 BV version. I found I had to add 15psi over the '06 small RP3 on our old bike.


----------



## PMK (Oct 12, 2004)

Okayfine said:


> We decided we're running the big can, '11 BV version. I found I had to add 15psi over the '06 small RP3 on our old bike.


And there is nothing wrong with this. Suspension is all about finding the best set of compromises for the application.

PK


----------



## DonP. (Dec 4, 2012)

Okay, did some fiddling with pressures and are feeling good at 180 psi in the shock and 100 in the fork. We plan on a 25 miler tomorrow on rolly fast fire road, I may bring the pump for on trail adjustments. I also had to rotate the shock to get access to the schrader valve as it's blocked by the left side rocker...


----------



## PMK (Oct 12, 2004)

DonP. said:


> Okay, did some fiddling with pressures and are feeling good at 180 psi in the shock and 100 in the fork. We plan on a 25 miler tomorrow on rolly fast fire road, I may bring the pump for on trail adjustments. I also had to rotate the shock to get access to the schrader valve as it's blocked by the left side rocker...


Without getting in trouble, how much does your stoker weigh?

PK


----------



## Keepiru (Dec 21, 2012)

We have a SR Suntour DURO SF9 on our Tandem. Even with the hard spring it was to soft at the beginning, but changing the elastomers to the hard (green) ones did the trick. The fork keeps up hard rides, has low flex and works like a charm.


----------



## DonP. (Dec 4, 2012)

pmk said:


> without getting in trouble, how much does your stoker weigh?
> 
> Pk


115


----------



## PMK (Oct 12, 2004)

DonP. said:


> 115


Explains the lower pressure

PK


----------



## rhxpro (Oct 9, 2006)

here is a link to my iild with the new suspension

http://forums.mtbr.com/tandem-mount...e-drive-lock-out-suspension-build-835481.html


----------



## Trails4Two (May 12, 2008)

White Brothers is coming out with a Double crown version of their Loop. I'll try to get some info/time on it and report back.


----------



## TandemNut (Mar 12, 2004)

Trails4Two said:


> White Brothers is coming out with a Double crown version of their Loop. I'll try to get some info/time on it and report back.


We've been selling it for over a year now. Much improved over the Magic platform.


----------



## mhopton (Nov 27, 2005)

Ok, here goes. New Fandango 29'r, new team, 260lbs. Experienced riders in North GA. Will spend 99% of our time on singletrack with lots of rocks and roots, quick turn-ins, etc. We opted to spec our tandem with a single-crown White Bros. Magic 100 rather than the newer dual-crown Loop as I wanted the quicker steering and handling characteristics. The fork felt great in the parking lot but was a bear to figure out on the trail. 

Initial settings were ~35-40psi, IMV somewhere in the middle and rebound - no idea.

Initially, we had a severe topping out clunk, which I understood to be too fast rebound - I just wasn't sure how to slow it down. I eventually found the knob below the right leg and found that very small increments had a big effect on rebound. I added pressure to 50psi, but that greatly limited movement. I then went full on and full off on the IMV setting, which I now understand is essentially a compression setting. 

By the end of the ride, we were ~20psi, almost no compression and still slightly topping out. The fork is new and we only put 3 hours on it yesterday, so I expect there to be intial stiction and expect it to loosen up with more hours. 

If you're having good success with this fork, can you give me some good initial settings? I'm not at all opposed to opening it up and changing the weight of the fork oil, or amount of oil, etc; in fact, I have a new bottle of Fox 10wt green oil on the workbench.

Thoughts?

For the rear, my stoker is using the ThudBuster with 2 blue elastomers. She is maybe 110lbs and...is quite sore today. We messed with her position on the seat to try to find the sweet spot to activate the thudbuster, but ultimately, I think she may need to swap out a blue elastomer for a softer gray one. Do these have a break in period? Any comments appreciated.


----------



## Trails4Two (May 12, 2008)

*Magic fork*

I tested a Magic on our tandem and never quite liked the feel of it. That said, they are pretty adjustable. If you don't get any better answers here, I suggest calling them direct. They are here in town with me and are good folks who like a puzzle. As for the Thudbuster, my wife used 1 blue/1 gray. She is 114lbs. They don't really "break-in" so much as "break down"; they will soften slightly as they get used - until they get old. They do have an age limit, so if they are older they can get quite firm.


----------



## PMK (Oct 12, 2004)

Yes, you will probably need Gray for one elastomer if not both. This may change over time, depending upon how much movement your stoker wants. The seat does float aft and down. My stoker, when we ran a Thudbuster LT on our previous Cannondales and Fandango, did not prefer a lot of movement, but did expect enough on unexpected hits.

You can set the initial preload via tightening the long bolt or loosening.

Gray elastomers are known to fail by splitting and going bye / bye. Blue and black do not. If you plan to ride on grays, ensure you understand how to replace the elastomer and carry a spare. Tools are simple, 10 mm box end wrench (cut down cheapy if you want) and an allen wrench. 

We have ridden with a few stokers in the low rider position. If it does happen, and an elastomer is not there to be installed, raise the seat, but realize it will be much further aft.

As for the fork...I have heard good, heard not so good, know they can be very adjustable.

First ensure no axle alignment concerns binding the fork legs.

Next, it should never be setup to top out, let alone top out with a clunk. Rebound should be set first, it is easy. Run the least possible without having the bike wallow or unsettle in a corner.

Compression, set the low speed first with IMV full open. This is based on feel to not wallow or be harsh. Once close, start adding a small amount of IMV influence, while POSSIBLY, reducing compression clicker by one or two clicks.

As for air pressure, I would run sag not carved in stone to a specific number, but rather approximately 20% of full stroke. On pavement, see how the bike turns. Pay particular attention to wheel flop. Adjust pressure slightly to lessen wheel flop. While riding off-road, see if the tire stays planted and note how much travel is utilized.

Setup will be different from a single bike, it should not feel soft and squishy, but rather firm and somewhat more heavily damped.

For comparison, a single MTB bike is like a motocross or woods race motorcycle when it comes to how the bike may feel. The tandem, while still performance based, is morre like a heavier sport road motorcycle. It will feel firm on account of the additional weight and stability required. Like a sport bike compared to an MX machine, the sport bike runs proper springs with a lot of preload and reasonable spring rates. The MX bike runs a soft spring with very little if any amount of preload.

PK


----------



## giff07 (Jun 7, 2010)

We have owned 2 WB Magic 100T forks. One on a Fandango the other on our current ECDM. Like the others I have never been able to quite get it sorted to my satisfaction. Both of them were dual crown versions. The main issue I feel is they are over sprung for our team weight(+/- 285). WB has great customer and technical support but they simply do not sell lighter springs for this model. They do for the Loop. I run the fork without any air pressure to get it to perform somewhat. WB tech says this is OK and it has improved performance. I have dealt with Eric Prinster ( i think thats his last name) at WB and he is very helpful. I have to say that I do not have a great understanding of suspension and learned most of what I know from Paul (PMK) at a clinic he did at the last AORTA event in N Carolina. Paul has also been very helpful in helping me get this sorted. I would start without air pressure and with the IMV in the middle position then set sag from there. We dialed down on the IMV to get sag correct. Test it in the woods and make sure you are getting full travel in most situations. If you find yourself bottoming out then add air pressure to suit. Ours would not hold lower air pressures.(less than 40 psi). Other than that the only advice I can offer is pay attention to what Paul has to say. Hope that helps!
Ed and Pat Gifford
the Snot Rocket tandem


----------



## mhopton (Nov 27, 2005)

Great replies Ed and Paul - thank you. I spent some time on the phone with the guys at WB, read the tuning manual and talked to Alex some more after stopping by the shop yesterday. We are heading out tomorrow for a good ride to continue the trial/error of fitting the bike and I believe that we have a good starting point. Essentially, we are going to run 10psi, which gives me about 25% sag. Rebound is difficult to tell given the short stroke of the damper and the IMV setting is 5 cliks out from full soft (-). I'm getting good movement on the pavement but the test will be on the trails tomorrow - will report back!

As for the Thudbuster, Alex continues with the theme of great service and tossed a grey bumper my way for my Stoker to test out - she's stoked.

More to come....


----------



## giff07 (Jun 7, 2010)

As a suggestion try running no air pressure and increasing the clicks on the IMV after trying it your way .My forks would not hold air pressure that low for even an hours trail ride. Let us know how it all pans out.
Ed


----------



## ds2199 (Sep 16, 2008)

mhopton said:


> ...As for the Thudbuster, Alex continues with the theme of great service and tossed a grey bumper my way for my Stoker to test out - she's stoked.
> 
> More to come....


Regarding the grey bumpers, as mentioned previously, they are not as durable, so make sure that you carry a spare and the tools to replace. We carry a small "leatherman" type tool along with our trusty multitool and have been able to replace and get on with the ride.

Depending on how flexy your stoker likes the suspended seatpost, you may want to try one blue with one grey, or possibly two grey?

Good luck wih dialing the suspension!


----------



## ebnelson (Oct 30, 2006)

On our 29er ECDM, we have been using a Fox 34 fork and float rear, both using CTD dampers since January and are very happy with it. We have the remote lever that allows me to switch compression damping in large increments on the fly for both front and rear simulanteously. I change the settings often during rides for up and down hills. I should measure, but I think my fork has travel reducers so that it is set to 110mm. Otherwise its a 120mm Float 34. 

The only thing I would change at the moment is to run the rear shock upside down since the adjuster cable moves up and down with the shock stroke. I have some different than stock reducers on the shock mounts so I can just flip them.


----------



## She&I (Jan 4, 2010)

That last post begs a question I'd thought of earlier...

What constitutes a "tandem rated" fork?


----------



## ebnelson (Oct 30, 2006)

One that works for me and my 95lb girlfriend. Of course!


----------



## Okayfine (Sep 7, 2010)

She&I said:


> What constitutes a "tandem rated" fork?


A fork the manufacturer will warranty even if they know it is being used on a tandem.

Beyond that the meaning is pretty flexible. You could say it means that the company has done the research and determined the fork is fit for tandem duty, but I don't know if that's the case 100% of the time. You could also make a case for the variety of tandem/Fox fork users giving it a defacto "tandem" rating. But since people do, IMO the only practical difference is warranty service.


----------



## ebnelson (Oct 30, 2006)

If a Fox fork folds in half causing in injuries that result in a lawsuit, Fox would state that the fork is not tandem rated and that they are not liable in any way. I can live with that knowledge and still use their forks. I wouldn't use their 32mm fork on a mtb tandem.


----------



## mhopton (Nov 27, 2005)

Ebnelson, I'm not familiar with a 34mm Fox Float for a 29'r that is 120mm travel. Or, is your ECDM a 26"?


----------



## ebnelson (Oct 30, 2006)

Sorry, 140mm travel reduced. The ECDM 29er handles poorly with the 140mm length from my experience.


----------



## ebnelson (Oct 30, 2006)

Correction again. My fork measures 135mm travel. My bad. We originally had the Talas 140 and hated the 140mm setting, preferring to leave it at 110mm. I just ride what my brother sends (works at Fox). No wonder our bike feels tall! It rides well enough now, but I may try to reduce it down to 120mm.


----------



## mhopton (Nov 27, 2005)

Ah, that makes more sense...the new 34mm stanchion options are appealing. I've spent some time researching the X-Fusion Trace RL2. It seems to have all of the desired characteristics to make it tandem friendly; 34mm stanchions, internally adjustable travel from 140mm down to 80mm (you have to open up the fork to make the adjustment - it's not on the fly), all aluminum machined parts inside, an actual damper with an adjustable shim stack and, what I think to be cool, a one-piece tapered crown. Supposed to be a lot stiffer than a two-piece. Anyway, always fun to read about new stuff!


----------



## PMK (Oct 12, 2004)

FOX 40 Kashima is the fork if you ride a 26. Shortened to a workable length for xc, it is the best MTB fork I have ever ridden. Not perfect but very close. 

Perfect would be adding 3mm more offset to the triple clamps, and reducing the forks lower leg offset by 3mm. Same amount of trail, just more steering lock angle. 

For us, the modified ATC was the way to go on our Fandango. These forks get a bad rep, but once easily sorted out are as reliable, f not more reliable than any fork out there. Hardtail wise they are capable of the speeds, and steering precision is justified in the double crown and fork tube diameters. 

PK


----------



## switchbacktrog (May 10, 2013)

Keepiru said:


> We have a SR Suntour DURO SF9 on our Tandem. Even with the hard spring it was to soft at the beginning, but changing the elastomers to the hard (green) ones did the trick. The fork keeps up hard rides, has low flex and works like a charm.


We also have a Suntour fork on our Lapierre tandem here in the UK, ours being the Duro FR20, 160mm of travel(coil sprung), 35mm stanchions and 20mm bolt through axle, 1.5" steerer. I've always used Fox forks with air springs on my single bikes but have been very pleased with the performance and plushness of the budget Suntour product. They also produce the Durolux, with air springs and travel adjust if you want to run it lower.


----------



## TandemNut (Mar 12, 2004)

During conversation that didn't take place with a person who doesn't exist a couple of days ago, some information came my way that indicates White Bros may have a 34mm stanchion platform single crown 29'er fork available in the future. If so, I believe a tandem-rated version of that will also be offered. Nothing concrete yet, but I believe it's being looked at. We've expressed our interest in the 29'er version if it becomes available. 
SR/Suntour USA has not been open to the use of their forks on tandems, despite the fact that they're spec'd on euro models. Perhaps it's due to the dedication of US PI attorneys. Either way, as a business, I have to honor the manufacturer's wishes on the use of their products. Believe me, I wish we had more options!


----------



## TigWorld (Feb 8, 2010)

I've been using a Manitou Nixon Platinum fork (145mm travel, air sprung, 20mm hex thru-axle) an our tandem and its been great. The air spring and infinite travel adjust make it easy to adjust. Separate shimmed comp and rebound pistons make it very easy to revalve and the sealed cartridge damper with sprung IFP keep damping consistent even after a few hours on the trail. No doubt its not tandem "approved" but its been working well for us.


----------



## dstke (Aug 5, 2013)

Just purchased a Manitou Marvel Pro 100mm for our recently acquired Cannondale M1000 XL/M (2006). We're about 320 combined weight. First ride and I could tell the travel was way too soft so I kept the control close to locked out. Also noticed general turning resistance that I hadn't felt when using the stock fork. Could this be due to shortened stem or just the softness of the fork? Will increase air pressure on our next ride. 

Appreciate any feedback on whether this is a good shock for the bike.

Doug


----------



## TigWorld (Feb 8, 2010)

dstke said:


> ...Will increase air pressure on our next ride...


Set the pressure so you get your desired amount of sag. Start somewhere around 25% sag and then see how much travel you're using. Tweak from there.


----------



## dstke (Aug 5, 2013)

Thanks TigWorld. Good rule of thumb. I'm on a mountain bike vacation with single bikes but will try it when I get back.


----------



## mactweek (Oct 3, 2011)

I read info on x-fusion website about their 34mm trace 29er fork. They claim their "unicrown" fork crown makes it 50% stronger in that area. Sounds like it should be strong enough for a tandem. Still I bet they won't authorize that use.


----------



## Sanchofula (Dec 30, 2007)

We're 340#, new team, riding a 29er Fandango, ours came with a White Brothers Loop twin crown fork. It was very easy to set up, we set the air pressure to 25% sag (75psi), set the rebound in the middle setting, then I vary the compression based on the terrain, usually middle for bumpy slow stuff and more lockout for fast riding. 

I can't really complain about the fork, it is plenty stiff, even pushing hard in tight turns it doesn't flex or get floppy, it stays on the ground and holds a steady line. I'm not sure what more we could want from a fork, maybe lighter or cheaper, but it works well so we'll keep it


----------



## eischman (Apr 5, 2005)

Need a tandem rated fork - triple clamp 100mm? WB loop for sale. I loved it on the trail but wanted a manual lockout instead of the smart shock

White brothers WB Loop Tandem Fork 29er 100mm like new Magura Louise disc - Buy and Sell and Review Mountain Bikes and Accessories


----------



## rigidftw (Mar 21, 2010)

switchbacktrog said:


> We also have a Suntour fork on our Lapierre tandem here in the UK, ours being the Duro FR20, 160mm of travel(coil sprung), 35mm stanchions and 20mm bolt through axle, 1.5" steerer. I've always used Fox forks with air springs on my single bikes but have been very pleased with the performance and plushness of the budget Suntour product. They also produce the Durolux, with air springs and travel adjust if you want to run it lower.


hi,
i'm thinking of putting this fork in a normal hardtail frame. do you think it would work sufficiently for a single rider as well?
how hard are the springs compared to normal forks?
cheers


----------



## switchbacktrog (May 10, 2013)

It should be OK. We have the spring wound back to its softest setting to get the right amount of sag. You might need a softer spring, but it depends on your weight really.


----------



## singlespeeder (Feb 17, 2006)

*Wow, not much has changed in fork suspension since the late 90's or has it?*

I have been tandeming since the late 80's. My first tandem was a Ritchey Skyline, worked beautifully, stiff, little flex, put the largest tires possible for the ridged frame and fork. Went down hard one day, my stoker was leaning off the bike in a gravel turn and bam, we got up and his shoulder was broken. Ahh, great memories. Later on, I purchased a Milkelsen tandem frame and built it up in 1997, it was built around 26" wheels. I called Cambria Cycles and asked what suspension fork would work on this bike, Red told me to use the Control Tech leading link fork. I did and it worked well, it was maxed out on air pressure, but it did work well. When we were out of the saddle, you would have the whoosh, whoosh noise of the front fork moving though it's travel. But, this bike handled so well, street and off road. Yes, I could get the front end to push....in the sand. I added yet another tandem in 1997, a Ventana with a Zyzzik (kant remember how to spell it, this fork was stiff, you could hit a curb straight on and the tandem would stall for a split second then roll on. Sold all of the tandems as we had kids and most of our cycling times diminished. Now, the kids are grown, we still have student loans to pay off, but, I just acquired an old Santana Rio, early 90's and searched for an suspension fork for it. I'm still amazed that there is little out there! The problem with the early Santana Rio is that the stock fork won't allow any tire larger than a 1.9" tire. At least if I go with a suspension fork, a 2.4 should work. So, I know that most people don't want to say which fork they are using because they are not tandem specked. Whoa, my question is: Is there any 15mm axle forks out there that will work on a tandem? Thanks, Mike



ds2199 said:


> Recently I have had a few converstions about suspension forks on a tandem. I would be interested to hear people's experience with their existing set up.
> 
> 1. What fork make/model and what frame make/model?
> 1a. single or dual crown
> ...


----------



## DHMASTER (Oct 12, 2010)

My tandem may not be of help, but a Fox 40 has been serving me quite well.


----------



## singlespeeder (Feb 17, 2006)

*I Can't Believe Someon Used A Rock Shox Indy!*

Check out this ebay listing: Santana Mountain Bike Tandem 26" Suspension Fork Rigid Fork Shimano LX XT XTR | eBay

The Rock Shox Indy flexed big time on a single bike, wonder how often it bottoms out? Now I would worry about fork breakage on this one!

Mike


----------



## mhopton (Nov 27, 2005)

We are using a non-approved Fox fork that has worked very, very well for us. It is a Float 29'r set at 130mm with a FIT damper and 34mm stanchions. I notice very little flex except under very hard hits - otherwise it is very stable with the tapered head tube.

Again, not an approved fork. We are a 280lb team and have had good success.

Sent from my SCH-I535 using Tapatalk


----------



## ds2199 (Sep 16, 2008)

*White Bros Loop*

I have no affiliation with this individual, but am always looking for tandem stuff on local craigs...

Looks like a fair price for a lightly used White Bros Loop! Applicable to this thread too!

White Bros dual crown Loop 29er fork


----------



## iLike29er (Apr 1, 2012)

*Suspension on Cannondale Tandem 29er*

Absolutely love this thread. Learning a lot from those of you contributing to technical setups.

So, I can get a killer deal on a newer Manitou Dorado Pro. Can anyone give any thoughts or advice as to how this fork would play with my 2014 Cannondale Tandem 29er? I'd greatly appreciate it. I'd like to act quickly on the fork before it's gone, but want to make sure it would be a good setup, or could be tuned to be a good setup, for our tandem.

@PMK, you've been helpful in recent conversations with a separate thread on fitting tires with this particular bike. You seem to have a lot of experience with suspension setups.


----------



## dstke (Aug 5, 2013)

Once I increased the pressure to a 25% sag I've had no problems with our Manitou Marvel Pro. Note that it did increase the height slightly which was a good thing as with the stock fork the pedals would occasionally hit the ground going over short rollers.


----------



## TandemNut (Mar 12, 2004)

iLike29er said:


> Absolutely love this thread. Learning a lot from those of you contributing to technical setups.
> 
> So, I can get a killer deal on a newer Manitou Dorado Pro. Can anyone give any thoughts or advice as to how this fork would play with my 2014 Cannondale Tandem 29er? I'd greatly appreciate it. I'd like to act quickly on the fork before it's gone, but want to make sure it would be a good setup, or could be tuned to be a good setup, for our tandem.
> 
> ...


I had Manitou build us a shortened travel version of the Dorado to test out on tandems. In the end, the spring rate was way too linear, and the amount of preload necessary to hold the fork up without having more than 50% sag was well beyond the max recommended pressure in the fork. After some discussion with the folks at Manitou, it was determined that the internals weren't suited for high weight loads and the accompanying pressures. So the chassis of the fork would work, but the guts don't.

White Bros will soon have the Stoke tandem fork out, and it's travel (100mm) will better match up to the Cannondale's geometry. There are also some other, non-tandem rated forks out there that would probably work better than the Dorado (great DH fork, but not that good as a tandem fork).

PMK is a suspension wiz!


----------



## TandemNut (Mar 12, 2004)

dstke said:


> Once I increased the pressure to a 25% sag I've had no problems with our Manitou Marvel Pro. Note that it did increase the height slightly which was a good thing as with the stock fork the pedals would occasionally hit the ground going over short rollers.


Which is one of the biggest knocks against the Cannondale - low BB height. Not sure why they do that, but it's a trademark of Cannondale tandems since back in the dark ages of rim brakes. The low BB height creates problems on technical trails, but rocks on flat trails. At least they've improved the steering geometry.


----------



## iLike29er (Apr 1, 2012)

TandemNut said:


> I had Manitou build us a shortened travel version of the Dorado to test out on tandems. In the end, the spring rate was way too linear, and the amount of preload necessary to hold the fork up without having more than 50% sag was well beyond the max recommended pressure in the fork. After some discussion with the folks at Manitou, it was determined that the internals weren't suited for high weight loads and the accompanying pressures. So the chassis of the fork would work, but the guts don't.
> 
> White Bros will soon have the Stoke tandem fork out, and it's travel (100mm) will better match up to the Cannondale's geometry. There are also some other, non-tandem rated forks out there that would probably work better than the Dorado (great DH fork, but not that good as a tandem fork).
> 
> PMK is a suspension wiz!


TandemNut, that's exactly what I needed to know. Thanks for that insight. I'll be passing on the Dorado in hopes of getting a more appropriate fork for our load.

Also, I understand your desire to recommend forks that have the manufacturer's backing for use on a tandem bike. Hypothetically speaking, if Fox was the only producer of MTB forks, which model would you "prefer" to use for a team weighing in at 340 lbs on the Cannondale Tandem 29er?


----------



## PMK (Oct 12, 2004)

Tandemnut, thanks for the kind words, Suspension wiz is more like suspension geek or in reality, just old and been working on the stuff a long time.

I would go with the tandemnuts Dorado advice. Personally I have no experience with that model. Also consider that some of the best forks ever made, moto and MTB have been conventional and not upside down.

The tandemnut and I have spoken about forks many times. I still have two ATC forks tucked away. Myself, I got them dialed in with some mods and consider them the best tandem hardtail fork for what the wife and I would ride. The fork tubes are huge and larger than a Fox 40. The steering lock or turning radius is almost 90 degrees. So they work well without flex and turn tight. Downside is they are not the lightest fork made since they run springs. They don't have clickers, but overall are stupid simple to dial in for hartail use. And they are 29, 26 or 650b just by moving the fork brace.

If I were to build another hardtail tandem (yes Alex it would be a Fandango), I would personally run a Fox 40 Kashima and modify the lower legs by removing enough fork brace to clear the tire.

I am a control freak, not personally but rather when riding. Tandems get over features in a controlled crash type style. They are heavy and flexy forks have vague steering plus also can deflect if ridden real hard. That's me, and for most people normal forks work. Also consider a lot has to do with your terrain. If rocky, get a rugged suspension platform and dial it in.

So Dorado would be a no in my book. Also, never rode a Maverick, but some folks swear by them. Cannondale development riders for that 29 were shown riding Lefties (Brave or Stupid), I guesss at a minimum single crown would be a dirt jump or similar style use such as the Fox 36 series.

PK


----------



## iLike29er (Apr 1, 2012)

@PMK, I've been looking for reviews and more details regarding the ATC forks. Is their website atcracing.com? It's kind of lacking with info and details on their forks and looks really outdated so I was wondering if they were still in business. I'm open to any brand for fork suspension. And I don't think I'm too much of a stickler on fork weight on a tandem. I just want to get something that will work for our weight and riding style (gravel roads, light single track, and occasional technical single track).

Regarding the Fox 40, I don't think I've seen a 29er iteration. Is that what you were referring to in modifying the lower legs to fit a 29er wheel/tire??

I saw the development guys riding the Lefty. I would never consider using that fork based on our weight alone. Scares me. 

What are your thoughts on using a Fox 34? We have plenty of those used for sale in the Denver area. I don't ever see a 36 used fork in 29er.


----------



## PMK (Oct 12, 2004)

In regards to the 34, many teams use them with good results. Not sure of their team size or terrain.

For the 40 and 36, a properly modified fork brace is required to clear the tire. There was a company doing this a while back. Done correctly there is still a respectable amount of material left after fitting a 29 wheel / tire.

Tandemnut is an ATC dealer unless things have changed. The design is older, certainly not a high tech lightweight fork, the website is out of date, and to get a smooth fork takes a little bit of mods. We put a lot of miles on our Fandango with an ATC. Never let us down that I recall.

Our ECDM came with one installed, and I purchased another just because and for spares. The ATC on the ECDM was not capable of keeping up with the Fox DHX 5.0 air rear shock and was replaced with a FOX 40 Kashima.

The modified ATC did work well with the ECDM stock RP series rear shock.

PK


----------



## PMK (Oct 12, 2004)

Just checked, the site is ATCRacing.com

PK


----------



## mhopton (Nov 27, 2005)

I'll chime in...for reference we are riding a Fandango 29'r with a Fox 34 Float that has been upgraded with a FIT damper. Our team weight, ready to ride, is about 285-290. We have put ~1700 miles on our Fox with a couple of bath oil changes only. I have however noticed that the press fit junction between the head tube and the crown is beginning to make a lot of noise, creaking and such, as we ride. I have also noticed that the bushings inside the fork legs are getting close to their limit as their is a noticeable increase in flex in the fork. We are exploring some options with TandemNut to look at replacing with the new MRP Stage platform, or similar, or possibly an X-fusion. Regardless, we'll have to do something by the Spring time even if just a total overhaul, bushings, damper service, etc., on the Fox.

I will say that the Fox works well and we use it hard on rough singletrack, rocks, roots, etc. It's seen a few race miles and a few gravel miles and a lot in between. Overall it's a great fork, but definitely not tandem rated as can be seen in the overall durability. Based on your riding, YMMV.

A shot of the Fox 34 on the front of our fandango.


----------



## reamer41 (Mar 26, 2007)

I have a Fox 34 RLC FIT on my solo-bike. 
It creeks (clicks.) and the crown. Not sure if it's the crown to steerer or legs to crown interface, but no matter. 

I would look at a 36 for tandem use, but not a 34.
In fact, I am considering getting a 36 for said solo-bike -- wanna buy a 34?
Seriously though, I have no idea if the clicking crown is an issue that will deteriorate or just continue to be annoying forever.

My first tandem had a ZZYZX fork -- the original ATC fork. It was a good platform, if a little crude. The damper was non adjustable and worn out... But the steering lock, and, after fitting 20mm axle, stiffness, and geometry were excellent.


----------



## iLike29er (Apr 1, 2012)

Regarding the modified arch on a 36 or 40 to clear a 29er wheel, are you aware of anyone utilized this mod on a tandem?? This is favorable because its really easy to find used 36 forks in 26. If this arch mod has not failed for tandem users in the past, then I may consider it.


----------



## PMK (Oct 12, 2004)

iLike29er said:


> Regarding the modified arch on a 36 or 40 to clear a 29er wheel, are you aware of anyone utilized this mod on a tandem?? This is favorable because its really easy to find used 36 forks in 26. If this arch mod has not failed for tandem users in the past, then I may consider it.


FWIW, failure or the brace is not a structural failure. The mod needs to be done properly but if it did fail, you should notice some less precise steering initially.

Complete failure still should not see the front wheel go away, the stanchions snap or steer tube slip in the crown.

If you do some looking, there were photos and the guy that was doing this posted on MTBR...somewhere.

PK


----------



## Bergrin (Jul 16, 2014)

We're riding a Rock Shox Totem on the front of our ECDM. It's got the stock 180mm of travel but I ride it without about 40% sag. The fork isn't as progressive as I'd like (I think the solo air totem would have been better) but the price was right. The stiffness and tracking is unreal and a huge step up from anything else I've ridden. Very happy to have a super stiff single crown fork on the front of the bike.


----------



## singletrackpursuits (Aug 9, 2004)

Awesome thread. I think I've skimmed through all 9 pages looking for my question, and didn't see it. Apologies if this has been asked before. 

So, wife and I are hooked on tandems, now. We've got our C-Dale road tandem for a pavement fix. Last year we bought a used, maybe 2008, C-Dale MTB Tandem to be used for mostly gravel, forest service roads, and an occasional jeep road. She's not too keen on singletrack, maybe someday. Lots of riding around North Carolina and West Virginia, lots of climbing too. 

Question: 380# combined weight, 26 inch x 2.0 tires/wheels, Thudbuster seatposts, what is the ideal shock for above described riding?

I saw all the Fox 34, 36, 40 references, but may be over-kill for us. I just want something to take the edge off washboard gravel, but still hold up on those same gravel downhills if we let go of the brakes and start tickling 40mph. The last thing I want is to have a major failure, and not only take myself out, but also the liability of taking her with me.

Dirt Jumper fork? 100mm travel, or more? Be nice to have a lockout, too.

Advice?


----------



## Trails4Two (May 12, 2008)

The DJ 100mm is a great fork for what you want. Avoid anything over 120mm unless you want to deal with the change in steering. I would try to stay with air forks unless you know you can find a heavy enough spring for your team. Go Ride!


----------



## Okayfine (Sep 7, 2010)

Not much choice for a 100mm travel, 1-1/8 steerer fork that will be safe for a heavier teams on a tandem. The DJ may be it, but I might even be weary of it given your team weight. And DJs are coil. I have a DJ on my single bike, but the necessary preload may render it less than plush for you.

FWIW we have a similar team weight, but run a Marz 66EVO. Too long in travel, but the 38mm stanctions make for a stiff front where it counts (and make up for the change in geo).

You may also reconsider the 2.0 tires, especially on gravel. IME 2.0 tires are too narrow on my single. We run 2.5 on our tandem.


----------



## richwolf (Dec 8, 2004)

Good thread, Getting back into tandeming after a long time off. Early to mid 90's KHS tandemanium bike with some upgrades. Put on a rigid 29er front fork but want to do a little more offroad with it. We want a better tandem but this will have to do for now. Want to a suspension fork and will go back to 26 inch wheel size. We are around 270 pounds of rider and want around 120 to 140 MM fork with lockout. Anything under $500? Straight 1 1/8 inch headset.


----------



## Okayfine (Sep 7, 2010)

We started off-road tandeming on a KHS, and put a DJ1 on it. No lockout, 100mm travel, but other parts of that bike limited it more than the 100mm. 

Marz has other stuff that might fit the travel (picked up a new $300 Marz 55 just recently), but straight steerers in that travel range with lockout aren't much available.


----------



## singletrackpursuits (Aug 9, 2004)

Anybody heard any horror stories about a Manitou Circus Expert, or maybe Argyle RCT? Each appear to be built for abuse, shorter travel (100-120mm), and come with a straight 1-1/8 option, and 20mm axle. Wish they were more than 32mm stanchions, but we are just wanting something to ride gravel and the occasional dirt road.


----------



## Okayfine (Sep 7, 2010)

Not when paired with 380# team weight:nono:


----------



## singletrackpursuits (Aug 9, 2004)

Okayfine said:


> Not when paired with 380# team weight:nono:


My fears too. I think a Marz 55 may be in our future.


----------



## richwolf (Dec 8, 2004)

I just bought a used 2013 Fox 36 Vanilla 180MM travel Fit fork with 20MM through axle for $400 on e-bay. 26 inch front fork. Will I be happy?? Also got a long travel thudbuster for my wife. Hopefully this will tide us over for a while.


----------



## PMK (Oct 12, 2004)

richwolf said:


> I just bought a used 2013 Fox 36 Vanilla 180MM travel Fit fork with 20MM through axle for $400 on e-bay. 26 inch front fork. Will I be happy?? Also got a long travel thudbuster for my wife. Hopefully this will tide us over for a while.


If this is going on the KHS, it will need to be shortened to reduce length and travel.

PK


----------



## richwolf (Dec 8, 2004)

PMK said:


> If this is going on the KHS, it will need to be shortened to reduce length and travel.
> 
> PK


I thought that might be the consensus but 
I am going to give it a shot. I have a suspension corrected 29er fork and wheel on the front now and it handles fine. Shouldn't raise it up too much more and I am going to run about 2 inches of sag. I figure if it is too much I can get my money out of it. Just can't afford a $4,000 ride right now!


----------



## richwolf (Dec 8, 2004)

I did some research on reducing travel on my "new" 180 MM Fox Vanilla fork and it seems like I can reduce the travel a bunch by adding home made spacers and cutting the spring. Found a nice thread describing the process on pinkbike.


----------



## PMK (Oct 12, 2004)

richwolf said:


> I did some research on reducing travel on my "new" 180 MM Fox Vanilla fork and it seems like I can reduce the travel a bunch by adding home made spacers and cutting the spring. Found a nice thread describing the process on pinkbike.


Many people don't realize how screwed up the bike becomes running too much sag.

Your plan is good, I hope the execution is good per the PB posts.

As for cutting springs, I have done it on some things, but not sure I would on a tandem fork. Seems easier to just find what you need since the spring you plan to cut is likely too soft and even adding spring rate by removing coils probably will still be too soft.

My opinion is a soft fork is vague handling that is tiring to ride. A properly sprung fork is lively and fun to ride at all speeds.

PK


----------



## richwolf (Dec 8, 2004)

PMK said:


> Many people don't realize how screwed up the bike becomes running too much sag.
> 
> Your plan is good, I hope the execution is good per the PB posts.
> 
> ...


Thanks for the feedback. The plan is to leave the spring a little long when I do the travel reductions so it will firm it up a bit. The fork comes with the stiffest spring so that helps out. Travel recommendations? 120, 130 or 140?? Building up a wide 36 hole rim and with the 20mm through axle and 36mm stanchions it should make for a controllable front end. Going with Geax 2.4 inch Goma tires.


----------



## reamer41 (Mar 26, 2007)

Agreed Paul! 

I tried riding our ECDM with a 170mm fork sagged at about 35-40%. It was sloppy at best and occasionally scary..


----------



## PMK (Oct 12, 2004)

richwolf said:


> Thanks for the feedback. The plan is to leave the spring a little long when I do the travel reductions so it will firm it up a bit. The fork comes with the stiffest spring so that helps out. Travel recommendations? 120, 130 or 140?? Building up a wide 36 hole rim and with the 20mm through axle and 36mm stanchions it should make for a controllable front end. Going with Geax 2.4 inch Goma tires.


If it were me accomplishing the travel reduction, two options

#1 I would find some 2x4's, and set them under the front tire with the spring removed. Sort out the expected height of the front while under load and see where the headtube angle ends up using a digital protractor, smart level or similar. (fork is fully compressed and the 2x4 represent the forks extension to the position with riders on board.

#2 With the spring removed, use a block of wood between the tire and crown / triple clamp to set the approximate desired travel, minus 30% for sag. (120mm travel would have a block of wood cut to represent approximately 90mm).

In simple terms, and the above steps are easy to accomplish, you want to have an idea of where the headtube angle will be with your new fork on the older frame. I would be cautious of less than 68 degrees but would prefer more like 70 to prevent the steering from becoming floppy when turned.

FWIW, the above methods to ballpark fork length do work well as opposed to an axle to crown dimension, unless you have the head angles for various length forks.

If you live nearby I will help you with it.

PK


----------



## PMK (Oct 12, 2004)

reamer41 said:


> Agreed Paul!
> 
> I tried riding our ECDM with a 170mm fork sagged at about 35-40%. It was sloppy at best and occasionally scary..


Quality shorter travel will be far better and more fun to ride than poor long travel...but quality long travel with good geometry beats pretty much everything except a better or stronger team.

PK


----------



## reamer41 (Mar 26, 2007)

Yeah. That was many years ago...


----------



## richwolf (Dec 8, 2004)

PMK said:


> If it were me accomplishing the travel reduction, two options
> 
> #1 I would find some 2x4's, and set them under the front tire with the spring removed. Sort out the expected height of the front while under load and see where the headtube angle ends up using a digital protractor, smart level or similar. (fork is fully compressed and the 2x4 represent the forks extension to the position with riders on board.
> 
> ...


Thanks for the offer. I live in southern Ca. The head angle of the KHS is 74 degrees so I have a lot of wiggle room. I run it with a suspension corrected 29 er fork and it handles fine but I will probably go a little lower than that.


----------



## richwolf (Dec 8, 2004)

Got the fork travel reduced, wheel built and ready to roll! Head angle without sag of around 69 degrees.
Reduced travel from 180 to 140 MM. Put in the stiffest spring (yellow). Built up a DMR 20MM through axle hub to a wide 36 hole Alex rim. Put on a 2.4 inch Geax Goma tire. Tried one in the back but it rubbed the chainstay. Went back to a 2.2 rear tire which fits fine. New Thudbuster LT seatpost for my wife.
Just been riding it around on my own but it handles good and the front shock is nice. First test ride with wife today.
Thanks for all the help!


----------



## richwolf (Dec 8, 2004)

Fork transforms the bike both on and off road. Whole front end is flex free and the suspension works very well. Nothing like a coil spring for smoothness. Our off road dirt excursion exceeded my expectations and makes the bike super fun to ride. The Goma tire out front grips well and rolls well.

Going to make a few position changes for me but this bike is ready for some single track. BB is plenty high so we aren't worried about that. Rolls over the bumps and rocks great.


----------



## StanleyJ (Dec 11, 2010)

<Disclaimer-The-Fork-Will-Exploded-And-You-And-Your-Stoker-Will-Die>

Since the following forks haven't been mentioned in this forum... anyone guinea-pigged the DVO stuff? Or perhaps a comment regarding how they might work out at tandem-loads? Either the massive Emerald DH (DVO Suspension | Emerald DH) with 36mm legs, with 42mm uppers, inverted-style (travel/ride-height restricted to say around 140~160mm); or the "Enduro Specific" Diamond (DVO Suspension | Diamond) which has 35mm legs?

</Disclaimer-The-Fork-Will-Exploded-And-You-And-Your-Stoker-Will-Die>


----------



## Okayfine (Sep 7, 2010)

From a stanction-diameter standpoint, either would be fine. We're a 360lb team and had an '06 Marz 66SL for a few years. 35mm stanctions. Was fine everywhere except diagonal impacts on sharp/square bumps. I could feel some flex in the fork when hitting stuff like that.

Only changed to a 38mm Marz fork because the air seals were dying in the 66SL. The 38 is noticeably less flexy, even above the 35 that I didn't really have problems with.

DVO people came from Marzocchi.


----------



## Johnbonn (Apr 7, 2015)

Anyone try the lefty? Heard the lefty max is the one to try? I see Calfee has one setup and a few other specialty builders do also. I know Cannondale doesn't condone it. Anyone?


----------



## XC Mike (Sep 26, 2004)

John I'm with you.... I would love to see a Lefty for the tandem...
I just picked up a 2013 Flash 29er that has a Lefty and I'm love it so far


----------



## Johnbonn (Apr 7, 2015)

We just sold our custom road tandem and want to build something unique and fun for the dirt and trails so i have a clean slate to start with. Thinking an older Cannondale MTN frame mount a lefty and discs with a 1x11 or 2x10? Any thoughts on which lefty the max, supermax, titanium....and how? Or if there is a better frame to start with? Was thinking tandem fatty and lefty but funding won't allow it right now.....anyone have a large or XL tandem frame to start with hook me up!! Any suggestions on the strongest lefty wheels out there? All thoughts and assistance is greatly appreciated!!


----------



## Tanduro (May 9, 2015)

My wife and I are building up a Ventana Gran Jefe tandem with 650B plus wheels and a suspension fork. Our team weight is under 300 lbs. with gear, and we ride mainly rough steep back roads and moderate single track. We are considering either a Carver Trans Fat inverted fork with a 135mm hub (also sold under numerous other small brand names), 
Trans-Fat Fork - Carver Bikes
or the Manitou Magnum Pro 34mm with a 110mm boost hub.
Plus Sized Gets Squishy with New Manitou Magnum Pro, Sun Ringle Plus Rims and Hubs. 
Really had some scary times with our current tandem under hard breaking on the steep and rough, so I want something reasonably stiff that can accommodate a 3.35" tire.


----------



## freerider1 (May 1, 2006)

1. ATC Racing T-5 2005 ECDM full suspension
2. Double crown
3. no lock out
4. 20mm thru axle
5. was 350 now 280

6. with my old stoker, freeriding ,downhill,drops and single track XC.
with my new stoker, lots of single track XC until he gets used to riding on a tandem.

7. fork handled well with heavier team, no issues,adjustments aren't too bad if yah know what your doing. with a lighter team, took air out of rear lightened up fork, and its sweet. fork is a bit heavy though.


----------



## She&I (Jan 4, 2010)

By what I've read here, I'm getting the sense that nobody is really concerned whether or not a fork has its mfr blessing for tandem use.

I would love to entertain the crop of great trail forks out there as an upgrade, but I'm leery of this issue. Equally suspect when someone recommends "great so far."

I want to ride some harder stuff, but with that terrain comes greater opportunity for a poor crash outcome. The head tube on our Fandango is the old style, so we are pretty limited in fork choices in any case, more so for "rated" forks.

We've run the Magic T100 our bike was spec'ed for with good results; just looking to make the bike more confident and capable without altering too much. What say the minds here? TIA.


----------



## killerisation (Nov 26, 2008)

*Hardtail xc fork for under $500*

I'm looking for a sus fork for our Shwinn Sierra tandem. I have a 26" front wheel with a 15mm thru axle. I am considering a Pike DJ and a Marz 350. We are a 300lb team (excluding bike) looking to ride xc.

Has anyone tried either?
Is there much difference between the DJ Pike and normal one?
Do we generally prefer springs or air for tandem use?
Can the spring in a 350 R be changed?


----------



## abikerider (May 8, 2007)

*Shortening a Marzocchi 66 RC3 Ti*

My wife and I ride and race an old 2000 ECDM. It came with a Strattos dual crown fork that I have been able to get a few years out of but really need to update, especially since it is impossible to get seals for it. I recently bought a 2010 Marzocchi 66 RC3 Ti fork for it which should be an awesome upgrade. I found it fairly easy to change the travel with a 2" piece of 3/4" PVC pipe to get it down to 130mm (I may change it to 140mm later on). The dilemma is that it is now next to impossible to get the top nut on the spring side screwed in because the original Ti spring has to be compressed 2" first. The two choices I have are to cut 2" off the Ti spring or find a suitable replacement spring. When finding a replacement spring, the problem is that nobody selling springs gives dimensions, only what fork it goes to.

I am asking for help from any suspension gurus to find a suitable spring. The original Ti spring's dimensions are:
free length: 315mm
inside diameter: 23.3mm
outside diameter: 32.3mm
rate: 5.4N/mm

Even something an inch or more shorter would be great to facilitate putting the fork back together. Ideally it should be 40mm shorter or 275mm free length. The inside diameter of 23.3mm is pretty important. The lower spring seat has a tube that sticks up 4.5" inside the spring as a guide and the spring needs to slide freely on it. The upper spring seat can fit an inside diameter as small as 20.3mm so one end could be smaller. Here is a picture of the lower spring seat and the spring for clarification.

https://drive.google.com/file/d/0BxnT0SDiN2hvRUkzb0ItZkdMRnc/view?usp=sharing

A steel spring of suitable size would be fine. If anyone has any recommendations such as Marzocchi 55 or Fox 36 springs that would fit that would be awesome. Otherwise I guess I will have to cut the Ti spring (seems like a waste). Thanks.
Mike S.


----------



## abikerider (May 8, 2007)

*Shortening a Marzocchi 66 RC3 Ti*

My wife and I ride and race an old 2000 ECDM. It came with a Strattos dual crown fork that I have been able to get a few years out of but really need to update, especially since it is impossible to get seals for it. I recently bought a 2010 Marzocchi 66 RC3 Ti fork for it which should be an awesome upgrade. I found it fairly easy to change the travel with a 2" piece of 3/4" PVC pipe to get it down to 130mm (I may change it to 140mm later on). The dilemma is that it is now next to impossible to get the top nut on the spring side screwed in because the original Ti spring has to be compressed 2" first. The two choices I have are to cut 2" off the Ti spring or find a suitable replacement spring. When finding a replacement spring, the problem is that nobody selling springs gives dimensions, only what fork it goes to.

I am asking for help from any suspension gurus to find a suitable spring. The original Ti spring's dimensions are:
free length: 315mm
inside diameter: 23.3mm
outside diameter: 32.3mm
rate: 5.4N/mm

Even something an inch or more shorter would be great to facilitate putting the fork back together. Ideally it should be 40mm shorter or 275mm free length. The inside diameter of 23.3mm is pretty important. The lower spring seat has a tube that sticks up 4.5" inside the spring as a guide and the spring needs to slide freely on it. The upper spring seat can fit an inside diameter as small as 20.3mm so one end could be smaller. Here is a picture of the lower spring seat and the spring for clarification.

https://drive.google.com/file/d/0BxnT0SDiN2hvRUkzb0ItZkdMRnc/view?usp=sharing

A steel spring of suitable size would be fine. If anyone has any recommendations such as Marzocchi 55 or Fox 36 springs that would fit that would be awesome. Otherwise I guess I will have to cut the Ti spring (seems like a waste). Thanks.
Mike S.


----------



## Okayfine (Sep 7, 2010)

Keep in mind that if you end up cutting the spring, it will increase the spring rate. It's linear, so if you cut 10% of the length, you'll increase the spring rate by 10%.


----------



## abikerider (May 8, 2007)

An increase in rate would be a good thing for the tandem. I also would need to fabricate a steel spring seat to go over the plastic seat for the cut end of the spring to sit on, otherwise it will dig into the plastic seat.


----------



## Okayfine (Sep 7, 2010)

Depends on your team weight, I guess. We have a '11 Marz 66 EVO and I'm 200ish pounds on the front. I don't have any preload dialed in, and don't find the fork soft at all. I'm not sure I'd want 10-15% increase in rate, but YMMV.


----------



## abikerider (May 8, 2007)

Well I went ahead and cut the spring by 40mm, found a washer that will work to reinforce the spring seat, and installed the spring. I just finished installing the fork on the bike but have yet to get the wife on it to check the sag and go for a test ride. So far so good.


----------



## PMK (Oct 12, 2004)

Did the ti spring you cut have coil or flattened ends. If the spring had flattened ends on each end, it is best to get it as close as possible to that before installing. Installing a cut spring with an open end in a flattened end design in most cases causes failure of something or excessive where as the spring buckles.

Also, since you can determine the available space for the compressed spring, you should determine if the cut spring when coil bound will be longer than the available space. Coilbinding a spring often breaks the spring perch or other components inside the fork, plus usually feels really bad on the wrists. 

Hope it works out for you, just be safe since the stoker most often gets the worst in a crash.


----------



## abikerider (May 8, 2007)

PMK said:


> Did the ti spring you cut have coil or flattened ends. If the spring had flattened ends on each end, it is best to get it as close as possible to that before installing. Installing a cut spring with an open end in a flattened end design in most cases causes failure of something or excessive where as the spring buckles.
> 
> Also, since you can determine the available space for the compressed spring, you should determine if the cut spring when coil bound will be longer than the available space. Coilbinding a spring often breaks the spring perch or other components inside the fork, plus usually feels really bad on the wrists.
> 
> Hope it works out for you, just be safe since the stoker most often gets the worst in a crash.


The spring had flattened ends but when I cut it I ground down the end on a grinding wheel till the surface of the end was flat with respect to spring's seat. I am also using a steel washer/bushing between it and the seat to prevent the spring from digging into the plastic. I also kept it cool by repeatedly dunking it in water while cutting and grinding the spring.

Also, I am shortening the spring by almost the same amount that I am shortening the travel and there is a lot of space between the coils. There should be no binding problems.

I had not considered the extra wear from the spring buckling. I have since decided to put the cut end on the bottom were it will be supported by the long tube seen in the link in my first post. This should help alleviate most of the buckling.

Thank you to all for your valuable input.


----------



## abikerider (May 8, 2007)

Okayfine said:


> Depends on your team weight, I guess. We have a '11 Marz 66 EVO and I'm 200ish pounds on the front. I don't have any preload dialed in, and don't find the fork soft at all. I'm not sure I'd want 10-15% increase in rate, but YMMV.


It could be that your fork came with stiffer springs. Our team weight is probable around 340lbs. Even after cutting the spring mine seems a little soft. I added air preload just to give it a little less sag. I will see how the test ride goes and and take it from there. I will report back about my experiences once we get a few rides in.


----------



## abikerider (May 8, 2007)

We just raced our tandem at the Prairie City Race in Folsom, CA with the Marzocchi 66 last night and loved it. It was so plush and stiff compared to the old Strattos. Sag was set to 25% (35mm) and the ziptie showed that we used about 115mm of the 140mm of travel. I thought the handling was fine. I was able to climb at a slow pace without any flop. I think I will be keeping the travel at 140mm but will lessen the compression dampening to utilize more of the travel. I had to use about 30psi of air preload. I think I am exceeding the recommended here but it is working well for us. 

Now that the fork is working pretty good I am noticing how bouncy the rear RP23 shock is. Time to fiddle with the dampening on it. I never really messed much with it other than getting the air pressure right.

Here we are at the race climbing a hill.


----------



## Okayfine (Sep 7, 2010)

Great success! :thumbsup:


----------



## mactweek (Oct 3, 2011)

I won a fork from Mountain Flyer magazine, It was supposed to be a 29'er boost fork. I asked for a 1.125 steerer so what I could get didn't really fit 29er wheels. I could fit a skinny 29er in there but with no mud room. The fork is a "German-A boost" fork. It has 36mm stations 100mm of travel and a sturdy 1.125" steerer. (also comes in tapered steerer." I ended up mounting it on our 10+ year old Curtlo 26" tandem. Our Dirt Jumper 1 was in need of a rebuild so I thought it might be a good option. I was able to fit a 26x2.75 dirt wizard in there, and could have fit a 27.5 but probably not + sized. We have only gotten to ride it on trails once, and that was cut short by mud but it felt great. Much more neutral handling than the dirt jumper. I think this was mostly due to the stiffer stations. This is a new fork on the market and I don't imagine they would want to call it tandem approved, but I will keep it on our bike for the time being and update this when I have more to report. We don't ride the tandem as much these days, My wife loves her Santa Cruz too much and I am now recovering from a broken rib.


----------



## mactweek (Oct 3, 2011)

_ said I would update when I had more to report. there is not much to say. I did get a second ride on it, this time with a friend who hasn't ridden on dirt in 11 years. She is a seasoned road rider (touring rider) and she used to ride a road tandem with her ex. She is taller and heavier than my wife, but she was a willing and capable stoker. We ended up riding some fun intermediate trails. There are several switchbacks on the route and we were able to clean all but 2 of them and that was due to communication problems, and not the lack of trying. The fork was very solid. I never felt like it was flexing too much, creating any vagueness in the steering. I am comparing it to an old dirtjumper 1 that never felt stiff enough for me. Both have 20mm. through axles. I don't know how available this fork will be, or if it will be "tandem approved" but so far I like it better than my tandem approved D.J.1._


----------

