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Thread: crank length

  1. #1
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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.

  2. #2
    hors category TandemGeek's Avatar
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    Quote 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.

  3. #3
    Senior Member zonatandem's Avatar
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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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    If she's an experience cyclist put her on a fixed gear so she can work on her spin. Otherwise pedal slower.

  5. #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.

  6. #6
    Senior Member Lost Coyote's Avatar
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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?
    Gravity kills.

  7. #7
    hors category TandemGeek's Avatar
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    Quote Originally Posted by Lost Coyote
    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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