different sizes of crankarms

Discussion in 'Cycling Equipment' started by vuce, Sep 11, 2006.

  1. vuce

    vuce New Member

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    I was wondering if it is possible to use different crankarms in size on the left and right side (for example 172,5 mm and 175 mm)... I have disproportionate legs due to having one leg 2 cm shorter than the other one, and i think different crankarms might help a bit... Has anyone ever tried anything like this?
     
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  2. fauxpas

    fauxpas New Member

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    If you use the shorter arm on the shorter leg, should be fine...
     
  3. nerdag

    nerdag New Member

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    A better solution might be to get an orthotic shim stuck underneath the cleat of the shorter leg - 2cm is a pretty big gap, and I don't think that a 2.5mm difference in length (5mm diameter) will feel very comfortable to ride.

    The force you'll need to put out with your shorter leg wil be slightly higher as well, which could lead to very unbalanced pedalling.

    HTH,

    n
     
  4. 531Aussie

    531Aussie Well-Known Member

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    it's a less than perfect soltution, because, while the shorter crank would be easier to reach at the bottom of the stroke, it would be further away at the top of the stroke. In other words, while the 2cm discrepancy might be rectified through the bottom of the pedal stroke, it would be doubled to (approx) a 4cm discrepancy through the top

    ....but, I guess having a lower pedal through the top of the pedal circle.......I'm not sure
     
  5. bobbyOCR

    bobbyOCR New Member

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    Maybe someone needs to invent an electronically or mechanically articulated sliding shortening/lengthening crankarm to compensate through all sectors of the pedal stroke :D

    Could go all the way to 'suspension crankarms' patent pending
     
  6. lumpy

    lumpy New Member

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    I've used an extra insole in the shoe with the shorter leg.
     
  7. dgregory57

    dgregory57 New Member

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    I seem to recall reading somewhere the ever popular "it depends" in answer to a similar question. Perhaps it was here or at BikeForums.net

    You can run different length cranks, and some do.

    I wouldn't worry about the power issue... it isn't important to exert more with the shorter leg unless your primary concern is that your acceleration is extremely smooth. Some people ride missing one leg, and I suspect they get very little torque from the leg that isn't there... ;)

    But, back to my point. I forget the specifics, but I read somewhere that there is a difference in how to deal with the length issue depending on whether the leg is shorter above or below the knee. The claim was that one condition lends itself to a shim, and the other to a shorter crank.

    Perhaps you should do a search, or seek the guidance of a doctor or other medical professional...

    There is a solution somewhere... You can find a way to be comfortable on your ride! :D

    Good luck!
     
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