# 29er hub width for tandems?



## nick3216 (Jan 10, 2006)

I figure that on an MTB tandem most of the issues go away...

long wheelbase, duh - got one already
bargelike steering (JOKE - OK!) - check
weight - like, have you ever picked up an MTB tandem?

What tandems do need is ability to roll over stuff - you ever tried to wheelie, stoppie or bunny hop a tandem? The big wheel would certainly help there.

The only downside I can see is the tendency of off-road tandems to eat wheels. Comes back to not being able to finesse over stuff.

While folk talk about increasing 29er wheel strength by increasing hub width they have generally only considered solos. 26er tandems already use wider hubs than 26er solos, so what hub widths should we be looking at for 29er tandems.


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## Singlespeedpunk (Jan 6, 2004)

Interesting question, I don't have the answers (sorry) but I can throw this in:

First off, how much more strength does a 140mm tandem hub give over a 135mm hub on a 26" wheel? Is 145mm even better? I remember Doug at Manitou c1990 making his frames with 140mm / 110mm hubs for better strength and some special Hugi hubs to suit them.

When tandem wheels fail do they flat-spot (frontal impact) or fold (lateral strength) or a combination of both? 

Is it ethcal to put 29" wheels on a Turner singlespeed tandem?   

Sorry...couldn't resist! 

Alex


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## nick3216 (Jan 10, 2006)

Singlespeedpunk said:


> Is it ethcal to put 29" wheels on a Turner singlespeed tandem?
> 
> Sorry...couldn't resist!
> 
> Alex


Singlespeed tandem. Are you mad? If there's one justification for gears tandems are it. 

As to the ethics - I seek advice from the 29er ayatollahs!


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## lelebebbel (Jan 31, 2005)

are you going to have your hubs custom made?
if not, i don't think there is too much choice. go for 150mm w/ 12mm thru axle rear (downhill specific hubs - 150mm with about the same flange spacing as 135mm hubs, but with symmetrical flanges)
and 110 w/20mm axle front.
I bet there are quite a few 150/12mm hubs drilled for 40 or 48 spokes.


You could also use one of those threaded 135mm singlespeed hubs with huge flange spacing, get a longer axle and screw on an old 6-speed cassette/freewheel.


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## nick3216 (Jan 10, 2006)

*It's a general query*



lelebebbel said:


> are you going to have your hubs custom made?


It's not related to a specific bike build.

There have been some good points raised about undustry standards for hub widths on this board.

I was seeking the opinion of those folks as to what they would propose as a new standard for tandems that would accomodate 29er wheels.


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## 20.100 FR (Jan 13, 2004)

lelebebbel said:


> You could also use one of those threaded 135mm singlespeed hubs with huge flange spacing, get a longer axle and screw on an old 6-speed cassette/freewheel.


I like this idea very much, and have access to all the lathe and CNC stuff i want.
Could you tell me where to look for old 6 or 7 speed freewhell ?


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## CBBaron (Dec 12, 2005)

Phil Wood makes disc brake tandem hubs in 145mm rear and 110x20mm front. I think they also make 160mm hubs for Santana that have threads for a drum brake (there are adapters for the threads to allow disc brakes). You could also use a 135mm SS disc hub on the front for increased strength. 

Craig


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## shiggy (Dec 19, 1998)

nick3216 said:


> I figure that on an MTB tandem most of the issues go away...
> 
> long wheelbase, duh - got one already
> bargelike steering (JOKE - OK!) - check
> ...


Go look at the tandem hubs DT Swiss offers


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## PeanutButterBreath (Oct 7, 2005)

Curtis Inglis rode a Retrotec 29er singlespeed at Sea Otter (or were those 26" Exi's?). He's a big guy too.


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## Cloxxki (Jan 11, 2004)

Since weight is only half as important, why not build the Tandem around Surly Endomorph tires? I rode a Pugsley bike recently, and it rolled awesome at 15psi on pavement. For dirt if can only be better, especially heavier weighted.

Extra strong rims = check
Volume for rolling over trail debris = check
Volume for comfort = check
Wheel weight per rider still on XC-level = check

Okay, so it's only 26x3.7", but it's better than plain old 26", IMO.


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## mikesee (Aug 25, 2003)

nick3216 said:


> While folk talk about increasing 29er wheel strength by increasing hub width they have generally only considered solos. 26er tandems already use wider hubs than 26er solos, so what hub widths should we be looking at for 29er tandems.


I'd use a 165mm DH hub if it were for my bike. DT and others make them in 32 and 36h.

MC


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## GlowBoy (Jan 3, 2004)

Hmm ... 29" MTB tandem. Don't see why not. The usual fit issues would apply: for example, my wife is too short for a 29"er solo bike, but no reason the stoker position couldn't still accomodate someone of her height. As with solo bikes, it could be the best of both worlds: the ability to run fat tires offroad, or skinny tires for the road, with BB height working about right for either depending on tire selection. The rolling-over-obstacles benefit of 29" wheels would be especially helpful on a tandem where you can't loft the front end. And the fact that 29" tires track markedly better though mud and sand would be of enormous benefit should you encounter those conditions while riding your tandem offroad!

I would think you'd want to go with at least a 150mm TA in back. Of course that would probably preclude the use of a BOB trailer, unless you fabricated some "dummy" BOB mounts near the rear dropouts.


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## Quasi (Jul 4, 2004)

I have been wondering whether Ventana might be looking into this. They could call it an "El Conquistitan."
_
Edit: Maybe an "El Capidor" would be better. _


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## Feldybikes (Feb 17, 2004)

Viscious has been making a 29er tandem for quite some time.

http://www.viciouscycles.com/frames-jeepster.php3

You could see what they use and figure out how well it works for them.


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## Quasi (Jul 4, 2004)

oopsie


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## El Caballo (Nov 22, 2004)

20.100 FR said:


> I like this idea very much, and have access to all the lathe and CNC stuff i want.
> Could you tell me where to look for old 6 or 7 speed freewhell ?


http://www.nashbar.com/profile.cfm?...and=&sku=11695&storetype=&estoreid=&pagename=
They have 7 speed too.


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## El Caballo (Nov 22, 2004)

lelebebbel said:


> go for 150mm w/ 12mm thru axle rear (downhill specific hubs - 150mm with about the same flange spacing as 135mm hubs, but with symmetrical flanges)


Some are symmetrical, some are spaced wider and dished (like 135mm hubs).

As mikesee said, you can get either 150mm or 165mm. Those are going to be the toughest hubs you can buy, and they will build the strongest wheels.


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## nick3216 (Jan 10, 2006)

*Missing the Point*

Yeah yeah, I could use a 165mm hub that's on the market, but you're missing the point.

I'm not asking what to use that's available now.

If I had a clean sheet of paper to develop hubs for 29er tandems how wide would you make them?


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## 20.100 FR (Jan 13, 2004)

El Caballo said:


> http://www.nashbar.com/profile.cfm?category=&subcategory=&brand=&sku=11695&storetype=&estoreid=&pagename=
> They have 7 speed too.


hum, thanks
24 is not enought for my riding.
I need a 34 !


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## PeanutButterBreath (Oct 7, 2005)

Shimano makes 6 speed FWs with 34T cogs, but they jump from 24T straight to the 34T.


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## DavoK (Oct 11, 2004)

Phil makes a great hub, but the seal on the freehub is not so good. The downfall of most rear hubs on tandems is the freehub. The only hub we've never ruined is a King. Of course this is on a 26" Ventana. Do downhill or freeride hubs have beefier freehubs? I don't think so. It's all about the torque on the freehub
DavoK


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## grawbass (Aug 23, 2004)

Cloxxki said:


> Since weight is only half as important, why not build the Tandem around Surly Endomorph tires? I rode a Pugsley bike recently, and it rolled awesome at 15psi on pavement. For dirt if can only be better, especially heavier weighted.
> 
> Extra strong rims = check
> Volume for rolling over trail debris = check
> ...


I think thats a great idea. :thumbsup:

If I was building a 29" tandem, I'd want 48 spoke wheels, but I'm not sure if the wider hubs (160-165mm) are available in 48. If you were going full rigid, you could have the fork built for 160-165 and run two rear wheels.


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## Soupboy (Jan 13, 2004)

nick3216 said:


> If I had a clean sheet of paper to develop hubs for 29er tandems how wide would you make them?


You have to consider the gating items here - notably chainline and clearance on the seatstays. I can't imagine needing more than 150mm with a properly built wheel.

MC - what kind of driveline are the DHers running with 165mm rear hubs - 1x__?

Seems like you'd have be running crazy wide BBs too. You'd end up bowlegged.

Also, since there are no susser forks wider than 110(x20mm TA) you're looking at turgid only.

Check out www.mtbtandems.com. Alex is a good guy and has built several high end MTB tandems (imagine that). Lots of Ventana content...beware.

If you search the forum you'll find that I asked a similar question a few months back. There was a lot of quality feedback.


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## Objectionable Material (Sep 29, 2004)

I've been riding off road tandems for 16 years. The problem with wheel strength in the back wheel doesn't have as much to do with the strength of the wheel as it does with the strength of the hub and the cogs. If you're riding on really challenging terrain and using the granny gear at all, you tend to go through cogs very often.

Wheel strenght is more an issue with the front wheel. Slow-speed handling with a 400 pound bike/riders combination puts an unbelievable amount of side loading on the front wheel. Think about going around switchbacks or riding up a rocky slope.

That said, my next tandem will definitely be a 29er. I'll just have to invest in a lot of rims and rebuild the front wheel on a regular basis.









The only 26er I own.

That reminds me. I need to take it out and play some time soon.

Pete


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## mikesee (Aug 25, 2003)

Soupboy said:


> You have to consider the gating items here - notably chainline and clearance on the seatstays. I can't imagine needing more than 150mm with a properly built wheel.


You can build dishless with most 150 hubs, but you get 15mm more flange width with the 165. _Anyone_ can appreciate that--even on a single bike.



Soupboy said:


> MC - what kind of driveline are the DHers running with 165mm rear hubs - 1x__?


All over the place. 1 x 9's, 1 x 8's, 1 x 5's, 1 x 4's.



Soupboy said:


> Seems like you'd have be running crazy wide BBs too. You'd end up bowlegged.


 Such a misconception, perpetuated for no good reason by a bunch of neurotic weight weenie racer geeks. The last thing you want to do (from an ergonomics _and_ comfort standpoint) is bring your feet _closer_ together. Wider is better, to a point. And standard cranks (even using 128mm wide bb's) aren't even approaching that point. Non issue.

MC


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## mikesee (Aug 25, 2003)

nick3216 said:


> Yeah yeah, I could use a 165mm hub that's on the market, but you're missing the point.
> 
> I'm not asking what to use that's available now.
> 
> If I had a clean sheet of paper to develop hubs for 29er tandems how wide would you make them?


Why do we need a new standard for rear hubs? What evidence do you have that the current standard is unacceptable?

My $.02 is that 150 hubs are ideal for 29" single bikes, even for most clydes or DH'ers. Few framebuilders even bother with 165 because 150 is sufficient. If you really need a durable 700c wheel, for almost _any_ application, 165 should suffice.

MC


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## jonassterling (Feb 15, 2005)

mikesee said:


> Y Such a misconception, perpetuated for no good reason by a bunch of neurotic weight weenie racer geeks. The last thing you want to do (from an ergonomics _and_ comfort standpoint) is bring your feet _closer_ together. Wider is better, to a point. And standard cranks (even using 128mm wide bb's) aren't even approaching that point. Non issue.
> 
> MC


Not meaning to start anything here, but one of the biggest proponents of a low q-factor I know of is Grant Peterson, hardly a neurotic weight weenie racer geek.

My personal experience is low Q-factor equals happy knees for me. I just got back on my KM after a few months of riding my fixed Cross Check almost exclusively. The KM has a much wider Q-factor and after shortish 2 hour rides my knees ache for a few hours afterward.

I'm also a bit bow legged which may have something to do with it, but I can notice the difference between a 107 BB and a 122.


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## CBBaron (Dec 12, 2005)

mikesee said:


> Such a misconception, perpetuated for no good reason by a bunch of neurotic weight weenie racer geeks. The last thing you want to do (from an ergonomics _and_ comfort standpoint) is bring your feet _closer_ together. Wider is better, to a point. And standard cranks (even using 128mm wide bb's) aren't even approaching that point. Non issue.
> MC


Maybe it is a non issue for some people but I find it hard to spin a wide Q-factor. I have a Pugsley SS, and two road fixies. The Q-factor is obviously much wider on the Pugsley and my cadence is much more ragged even on the road. I feel I spin much more smoothly on the narrow Q track bike. I have not had any pain issues with the Pugsley and the width is not much of a problem on the trail but if it was possible I would perfer a narrower Q.

Craig


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## nick3216 (Jan 10, 2006)

*For Cat Killing*



mikesee said:


> Why do we need a new standard for rear hubs?


I'm not sure we do.



mikesee said:


> What evidence do you have that the current standard is unacceptable?/QUOTE]
> 
> Absolutely none.
> 
> ...


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## mikesee (Aug 25, 2003)

nick3216 said:


> I was just curious seeing as there's been talk on at least one other thread (http://forums.mtbr.com/showthread.php?t=190125) about increasing hub width for 29ers to get back some of the wheel strength lost by making them bigger.


If you can filter through all of the off-topic stuff and the many tangents, that thread makes it clear that the biggest problem lies with front disc hubs and 29" wheels, although 26" disc front wheels have gotten weaker too.



nick3216 said:


> Seeing as off-road tandems seem to me to be an ideal application of the bigger wheel, and 26er tandems already use wider hubs than 26er solos, it struck me that the debate on a new hub width for 29ers was likely going to end up in the same position, having one standard for regular 29ers and one for tandem 29ers.


You might get a few single bike riders (on this board for sure) that'll argue that one...

As to the dual standards, they're already out there, it's just a question of discussing it with your framebuilder before getting started. The reality is that stock 29" single bikes will be using 135mm for a long time, but custom singles and tandems can easily use 150 or 165 as appropriate.



nick3216 said:


> So, I just thought I'd ask folk to consider it.


Sure. Good idea.



nick3216 said:


> Some other folk need to back up their assumptions* with evidence too. For instance which wheel really is weaker? Where is the evidence that front wheels take the hammer?


I've folded three 29" front disc wheels, and zero 29" rears. My personal 29" rear wheels require more truing than the fronts, but they've never failed catastrophically.



nick3216 said:


> I've trashed zero front wheels and three rears on off-road tandems. The first was a carbon wheel that disintegrated.The other two were wide and allegedly strong DH rims destroyed by flat spotting the rims not by crisping them. Solution: Narrow deep section rims. No wheels destroyed since, the compromise is that it limits our tyre width.


I love the durability and rigidity that deep section rims give (pics below), but until we get some wider ones their use will always be limited to xc racing and light xc riding.

Thanks for the measured response.

MC


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## nick3216 (Jan 10, 2006)

*Twin Discs*



mikesee said:


> If you can filter through all of the off-topic stuff and the many tangents, that thread makes it clear that the biggest problem lies with front disc hubs and 29" wheels, although 26" disc front wheels have gotten weaker too.


At the risk of leading us off topic briefly to make an on topic point I think perhaps we should consider the standards for disc hubs.

The biggest issue we have on the front of our tandem is brake steer.

We rode down the Fort William DH course and under heavy braking going into the the hairpins at the top the forks (Boxxers) were visibly twisting under braking forces. We had stopping power, but the brake steering badly affected handling.

In addition to messing up steering the uneven braking force on the front wheel when there are side loads on the wheel from cornering is a combination that is just trying to pretzel the wheel.

I've always maintained that while twin front brakes are not necessary to increase stopping power, from an engineering viewpoint of equalise the braking forces on the wheel and forks they make a lot of sense.

I know twin brake systems have been tried before and never took off. I'm not sure whether it is an idea that should be consigned to history or one that will rear it's head again in the future and need yet more tweaking of hub standards.


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## Thylacine (Feb 29, 2004)

Interested in your views on q-factor, Mikesee. Ergonomically I think it should mimic your natural stance, and annectdotally I know my road bike feels much more natural than my mtb when switching to/from.

What are you basing your comment _"The last thing you want to do (from an ergonomics and comfort standpoint) is bring your feet closer together. Wider is better, to a point."_ on?

From my research, and factoring in all the compromises that have to be taken into account, a 125mm front and 150mm rear provides what I think is the optimal for 29ers in an xc/trailbike arena (ie: where you actually have to pedal  ) ElCaballo and VentanaOz both agree with me on this.

To the OP, I think sticking with DH or existing tandem rear hubs for a 29er tandem is the answer to your question. I don't think a new standard is warranted for the rear (as they sort of already exist) but I think it would be nice to have a wider front standard. If certain people aren't having problems, then obviously it's not a solution to anything _for them_, but I think an improvement is an improvement and should be persued for it's own sake regardless.

Actually, that sounds like I have lofty ideals, but it's really pure selfishness - I just want my next personal 29er to be as good as my 26ers, and I don't think we're quite there yet.


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