Crank arm lengths???

bluedoggy Posts: 285
edited September 2012 in Road buying advice
Crank arm lengths??? Why are they different?
So what benefit say is a 170mm has over a 175mm? Or disadvantage?
Wilier cento uno.


  • sungod
    sungod Posts: 16,859
    in general, longer legs, longer cranks

    but there's more to it than that, and opinions vary as to what is best, some comments of the subject here...
    my bike - faster than god's and twice as shiny
  • StillGoing
    StillGoing Posts: 5,211
    If the crank arm length is too long, the rider has to lower the seat to get the correct leg extension when at the bottom of the stroke. Conversely that means the leg at the top of the stroke will be compressed more than it should causing problems getting power out. I have heard some TT riders are moving away from elyptical rings to shorter crank arms to avoid dead spots but I have no idea how true it is.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.