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Discussion Starter · #1 ·
Are there any rules of thumb regarding BB height on 29er frames versus conventional 26in frames?

I guess without giving it much thought, I assumed 29ers would ride higher - but I just picked a 29er hardtail on clearance the other days (mainly for the parts) and found on riding it that I was getting a lot more pedal strikes than usual.

I got home and measured the BB height at 12in - my Yeti 575 is 13.5. That seems like a big difference - enough that I could notice it.

Is the 12in height typical for a 29er frame (this is a Fuji Tahoe FYI)?

just curious.
 

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doctapow said:
Are there any rules of thumb regarding BB height on 29er frames versus conventional 26in frames?

I guess without giving it much thought, I assumed 29ers would ride higher - but I just picked a 29er hardtail on clearance the other days (mainly for the parts) and found on riding it that I was getting a lot more pedal strikes than usual.

I got home and measured the BB height at 12in - my Yeti 575 is 13.5. That seems like a big difference - enough that I could notice it.

Is the 12in height typical for a 29er frame (this is a Fuji Tahoe FYI)?

just curious.
That is the difference in hardtail vs full suspension rather than 29" vs 26".

Full sussies have higher BBs to accommodate the suspension travel.
 

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29er HT's have similar BB height... but more BB drop (lower relative to the hub height)... which actualy lowers the center of gravity of the bike vs a higher bb :)
 

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Discussion Starter · #4 ·
thanks for the replies.

it seems then that the 12in BB height on my 29er HT is not unusual - the Niner website claims 11.7in for the SIR9 which is a pretty popular and mainstream frame.

I read some backthreads here stating too that the 13.5in height on the Yeti 575 is also on the high-side for a FS 26" bike - so between that and the hardtail/FS differences, it is a noticeable difference. I definitely could feel the difference.

So is 12in pretty typical BB height for a 26" hardtail as well?
 

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doctapow said:
thanks for the replies.

it seems then that the 12in BB height on my 29er HT is not unusual - the Niner website claims 11.7in for the SIR9 which is a pretty popular and mainstream frame.

I read some backthreads here stating too that the 13.5in height on the Yeti 575 is also on the high-side for a FS 26" bike - so between that and the hardtail/FS differences, it is a noticeable difference. I definitely could feel the difference.

So is 12in pretty typical BB height for a 26" hardtail as well?
Yes, "normal" range is 11.7-12.2" for a hardtail. Personally I prefer 12.5-13", but I also use 185mm cranks.
 

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I noticed the same thing...

When I got a 29er, I thought I'd have less pedal strikes, instead I have more. Sure enough, my 26" FS BB is 1" higher than my 29er BB. It was disappointing...
 

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I agree with what others have said. No reason to have a different bottom bracket height from 26 to 29 BUT there is a reason to have a different BB height with full suspension. Your hardtail is pretty normal. You'll get used to it and maybe even come to like it.

I, for one, like a relatively low BB. I had my custom 29er specced with a 11.8" bottom bracket height (70mm of drop). I run 175mm cranks and a rigid fork, so the height doesn't vary as the fork compresses. I like the feeling of being "in" the bike, rather than on it. My cranks are cheap and ancient, so I don't worry too much about the occasional strike.
 

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Discussion Starter · #8 ·
OK, all a part of getting educated for me - maybe I will come to like it. It definitely feels different than by FS 26" - feels fast on the flowy parts of the single-track and more stable.

I also have relatively big platform pedals on my 29er right now which exacerbates the problem compared to the Candy's I run on my Yeti. Probably a lower profile pedal would help some.

cheers,
 

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Kathleen in AZ
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John_Biker said:
My cranks are cheap and ancient, so I don't worry too much about the occasional strike.
That's funny... occasional strike? I can pretty much guarantee that any part I buy and even the frame itself will be a scratched mess in just a few months of riding time. Smooth trails are few and far inbetween in my neck of the woods (desert) and I am A-ok with that! I just bought a fancy smancy pair of Twenty6 pedals for my new Lunchbox. They are beautiful right now, but give them a ride or two... I should take a pic before I mount them on my heavily scratched month-old XT cranks
 

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doctapow said:
Are there any rules of thumb regarding BB height on 29er frames versus conventional 26in frames?

I guess without giving it much thought, I assumed 29ers would ride higher - but I just picked a 29er hardtail on clearance the other days (mainly for the parts) and found on riding it that I was getting a lot more pedal strikes than usual.

I got home and measured the BB height at 12in - my Yeti 575 is 13.5. That seems like a big difference - enough that I could notice it.

Is the 12in height typical for a 29er frame (this is a Fuji Tahoe FYI)?

just curious.
With the increased traction and overall stability of the larger wheel, I find myself enjoying a slightly higher BB (12.2") on technical climbs that I would not have been able to clear with the smaller wheels. The higher BB allows me to stay on the gas longer.
 

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BB height and wheel diameter are NOT inextricably interwined. There is nothing unique about a particular wheel size that will dictate BB height.

As has been noted, BB heights on FS bikes are typically higher than for a HT, but you'll find that if you take into account the proper sag, the BB height will come in line with the typical HT, albeit a tad higher to account for additional suspension travel. The really high unsagged BB height is one reason I don't care for a long travel 26" wheel bike. It seems you need a step ladder just to get on 'em. I'd rather have a 4" travel 29er with minimal sag than a 5.5 or higher travel 26" bike with lot's of sag.
 
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