# Tandem drivetrain options



## Oh My Sack! (Aug 21, 2006)

Stuck in the house with the Creeping Crud sickness today. It's a dangerous thing because I have to much time to start thinking about things....like bike mods! 

This C'dale MT800 I just picked up is set up as a 3x8 with an 11-30 cassette and 26/36/48 triple chainring set. XT front and rear hubs, XT RD, LX FD, and Alevio shifters (according to old spec manual). We'll be on pretty flat road terrain for a while as we get adjusted to this riding. The wheels are turning about the gearing on this for our future riding conditions as we branch out on our country roads and eventually, the more sanitized singletrack networks we have locally. My full squish bike is a 2x10 with 11-36 and 24/38 chainrings. I just upgraded my road rig to Ultegra 11 spd with 11-32 and 50/34 chainrings. Though we're not feeling it yet, I'm envisioning a pretty significant loss of low end gearing on the tandem when we get to the hills. I understand we have 2 engines onboard but the rear engine isn't going to have a whole lot of output for quite sometime as she builds her legs and cardio. I can get an 11-32 cassette real easy and help a bit but this "at home boredom" also has me wondering about an even more significant modification by bringing this bike into more modern specs with a 3x10 or perhaps 3x9 if the freehub wouldn't support the 10 spd cassette (I think it would, though?). Shifters, RD's, and FD's of XT and even XTR quality can be sourced for what I would consider reasonable costs. 

What is the norm for newer tandem drivetrains, now? 2x10? Or still running triples? I'm guessing my issue with going to 3x10 would be chainring issues with the skinny chain? Depending on sources, having to replace chain rings would maybe take this beyond cost effectiveness.

Thoughts?


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## hogprint (Oct 17, 2005)

I also have a craigslist purchased MT800 and am about 3 years ahead of you on this journey. From stock I now have a FOX 40 up front, Hayes disc brakes on a new wheelset and just ordered a 1x11 set up from Chain Reaction. They have (well expect 8/22) the new 11-46 (!) rear cassette and I went with XT shifters and rear mech. Ditching the 3x up front with a 38T Race Face HiLo chain ring. Won't have the results till around labor day but I can understand the wheels turning upstairs.

This is a great site to compare drive train options and see exactly what you may gain/give up on gears. HTML5 Gear Calculator


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## PMK (Oct 12, 2004)

I am retro...Always had a certain fondness for the solid shifts of 8 speed. Actually just installed XTR 950 8 speed on my single bike. 

Not that it matters, we run a 3x9 XO setup on our ECDM. It works.

Actually, we also run XO 9 speed on the road tandem also, but a near straight block cassette and a great granny that we hardly use.

It just shifts so good. But I have not tried DI2.


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## Oh My Sack! (Aug 21, 2006)

Once I got the sticky shifters from lack of use issue squared away, the 3x8 does shift nicely with the XT. I'll go play around with the Gain Ratio calculator on Sheldon Brown's site. Maybe just going to an 11-32 and drop the small chainring to a 24 (if I can) would be a sufficient reduction.


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## ebnelson (Oct 30, 2006)

3, 2, or 1 chainrings all work and have their place. I'd put that 24 granny on and put the biggest 8 sp cassette you can find on.


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## Oh My Sack! (Aug 21, 2006)

Just had a revelation. I forgot what I had stashed in a box. a couple years ago I did a 2x10 conversion from 3x9 on a 2004 S-Works M4. They just let me keep all the super clean XTR components that were removed. I have XTR shifter/cable brake combos, a 9 spd long cage RD, and the crankset which won't help. It was running an 12-34 XTR cassette and I think it's a titanium spider. I was hoping I could salvage the 24T chain ring off it but the C'dale is a 5 spoke not 4. I ran the numbers on Sheldon B. and with the 26T, I get a 1.4 GR. That's good. If I go to a 24T, I end up at 1.3 GR. that's pretty granny.

Anybody see an issue with the brake levers going from mech disc use to the rim brake application? There's no mechanical advantage built into either so I'm assuming I should be golden. The only thing I don't have is an XTR FD since the S-Works ran an e-type FD. I'm already seeing a couple "period correct" FD's on ebay that i can scoop to complete the project.

I guess my only unknowns at this point is confirming that a 9spd cassette will fit an 8 spd freehub? And the 9 speed chain shouldn't be an issue for the current chainrings? I'm making an assumption that those 2 items will crossover?

Would love to hear others thoughts before I dive in.


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## mactweek (Oct 3, 2011)

9 speed cassette will fit on the 8 speed freehub. They use the same freehub, so no special spacers are needed. Are you planning to take off the disc brakes to replace them with the xtr v brakes? Just use the xtr levers with the mechanical discs they will work much better. If brake levers are for older cantilever style brakes you will need to use (road) mechanical brakes as they are designed for a shorter cable pull to match those levers.


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## TandemNut (Mar 12, 2004)

I'd suggest riding it some before you do much to it. If your wife doesn't like it and you don't end up doing serious miles off-road, it will do fine in stock form, with the afore-mentioned smaller chainring/larger cassette swaps. If you do end up doing lots of miles, you'll want to look at newer platforms before putting a lot of money into a 26" hardtail. The new frames and wheel platforms are much more comfortable, capable, and handle better (although PMK may argue with me on that point). It's much easier to figure out what's needed when you find the weaknesses while riding...


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## Oh My Sack! (Aug 21, 2006)

All good points. I will wait till we get a number of rides under our belt. The brake levers may pose an issue. I didn't plan on using discs. The hubs are not set up for that. It has Coda side pull cantilevers on it with Tektro levers. I'm not so sure the cable pull is adequate with the XTR lever. I'll have to check it.


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## PMK (Oct 12, 2004)

If it were me, I would not use the XTR Ti cassette since they tend to fold under power during a climb or getting over stuff.

Alex is correct about technology advancing. The XTR shifters and brakes will work. The frame is good, and has better geometry if it is an earlier non disc tab style frame.

If you plan to road ride initially, I agree with Alex and say kept it stock with stock gearing. If you plan to go off-road, I would guess the 5 arm cranks are Sugino and have 74 110 chainrings. You might be able to buy a set of Sugino cranks with the smaller 58 94 chainring pattern and get down to a 22 granny, allowing you to run a 22/32/42 with a 30 or 32 on the back.

Start searching for a Thudbuster or Chiropractor. The back of the Cannondale is stiff and rides accordingly.

Ride the wheels off it, and save the money for a newer entire machine if you get into it seriously. If you remain casual about tandeming, the MT800 will last a long time.


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## PMK (Oct 12, 2004)

Alex, we don't argue, sometimes we simply prefer different setups and the handling that comes with it.

One of the things I so love about a good setup is the stoker is ok with back end hanging out as the bike steers from the back and less from the front. Obviously not what everyone prefers. In big open spaces steering is less of a factor. The 29 Fandango has superb geometry where the added grip does not overpower the steering and the entire package does fine leaned over in corners or less leaned over. There is no wheel flop which is an important consideration as speed increases. A tandem with wheel flop does fine up to a point then truly shifts the weight and becomes a handful and tiring to captain.


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## Anthem1 (Feb 9, 2008)

I just built up a second hand Fandango 1x10, performance is like my single bike 1x10 and very economical.
2-Deore close out crank sets
2- black spire 36T chain rings mounted in the outer position.
1- Race face 32T narrow/wide chain ring mounted in the middle position on the stokers crankset.
1-XT 11-36 cassette.
1-Sram X.9. shifter. 
1-Sram X.9. Type 2 shorty derailleur.


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## ds2199 (Sep 16, 2008)

Anthem1 said:


> I just built up a second hand Fandango 1x10, performance is like my single bike 1x10 and very economical.
> 2-Deore close out crank sets
> 2- black spire 36T chain rings mounted in the outer position.
> 1- Race face 32T narrow/wide chain ring mounted in the middle position on the stokers crankset.
> ...


This is a good and economical way to go. That said, I would not be able to get away with the 32t chainring with the terrain that we ride.

Or put another way, we are not worthy of that big gearing!


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