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Tandem Cycling A bicycle built for two. Want to find out more about this wonderful world of tandems? Check out this forum to talk with other tandem enthusiasts. Captains and stokers welcome!

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Old 09-13-05, 12:25 PM   #1
SRidge
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crank length

Common tandem crank sets are 165-170,170-170,170-175,etc.,ours is 170-175. My single is 172.5,hers is 165. I like to keep a high cadence. Our problem is when I'm spinnnig comfortably she's bouncing of the seat. Is there any reason why I shouldn't go with a 172.5 on the front as this will have us spinning about the same circumferance.
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Old 09-13-05, 04:33 PM   #2
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Originally Posted by SRidge
Is there any reason why I shouldn't go with a 172.5 on the front as this will have us spinning about the same circumferance.
Not really...

Some will repeat the argument offered by some builders that a longer than usual 1/2 bike crank is preferrable for a tandem captain since it will provide for increased leverage. Frankly, I think it's just a way of glossing over the decision to use 175/170 cranks as the default standard, much the same as most 1/2 bikes end up with 170 as a default, regardless of how large or small the frame is.

The flip-side of the coin is, not all cyclists are sensitive to a +/- 5mm change in crank length, myself being one of them. My fixed-gear bike has 165mm cranks, my singles have 170mm, and my tandems 175mm; go figure. It takes me about a mile to adapt but, then again, I'm just an old hack rider these days.

Last edited by TandemGeek; 09-16-05 at 09:18 AM.
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Old 09-13-05, 04:40 PM   #3
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If you are comfortable with what you are using, keep 'em. If not, change.
We have been riding 170mm cranks, front and rear, for 30+ years. Pilot is 5'7", stoker 4' 10 3/4".
Some folks will never know the difference of 2 1/2, 5 or even 10mm in length; others would be quite sensitive.
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Old 09-13-05, 06:41 PM   #4
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If she's an experience cyclist put her on a fixed gear so she can work on her spin. Otherwise pedal slower.
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Old 09-16-05, 07:58 AM   #5
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I've had 170s to 177s on racing bikes, but settled on 175s for both road and TT years ago. I hvae 170s on my tandem and they are fine.
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Old 09-16-05, 09:47 AM   #6
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Is there some reason you can't use 165s for the stoker and 175s for the captian? If you are looking for a smooth spin, why not?
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Old 09-16-05, 10:20 AM   #7
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Is there some reason you can't use 165s for the stoker and 175s for the captian? If you are looking for a smooth spin, why not?
None whatsoever. I believe we recently covered this in another thread:
Timing chain rings
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