crank length

ndm8966
ndm8966 Posts: 36
edited May 2010 in Workshop
I know this is more about feel and comfort but is there a formula for working out the "ideal" crank length?

Comments

  • max888
    max888 Posts: 206
    Not so much a formula as a guide from German bike magazine "RoadBike"

    Stride Length(mm) - Crank Length(mm)
    >/700 - 165.0
    >/730 - 167.5
    >/760 - 170.0
    >/790 - 172.5
    >/820 - 175.0
    >/860 - 177.5
    >/900 - 180.0

    FYI >/ is meant to "mean greater than or equal to"
    Cannondale CAAD9, CAAD5, RZ140, F5

    http://dottyjumper.posterous.com/

    http://twitter.com/#!/MaxGloger
  • Burghley
    Burghley Posts: 412
    Hi

    There is no formula to work our crank length, and I'm not sure it's necessary.

    My bikes have a mixture of 170, 172.5, and 175 cranks and you would be hard pressed to accurately tell which one is which at times (remember, that's only 5mm difference between the shortest and the longest).

    Shorter cranks are probably better if you prefer a fast cadence. Also, if you have tight hamstrings/hips the shorter crank will not push your knee too high and cause hip rotation. Longer cranks probably suit big strong riders best - Miguel Indurain was reputed to ride 180mm cranks, for example!

    As a general rule crank length is defined by most manufacturers according to the size of the frame in much the same way that stem length and handlebar width is. In other words, the bike is made to fit as many people as possible - but it may not be right for YOU!

    If you are happy with your current setup, it's probably not worth the expense of changing crank length - unless you are upgrading of course.

    Rgds

    Pete
    www.bikesetup.co.uk
    miles more cycling comfort

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