Crankarm length

[JPW#]

just google it, but these days 175mm is the norm on mtb's and road bikes, unless ur really short x 10

[Akkedis]

Got this from the net.

 

"One writer in a major magazine article quite a few years ago claimed that after considerable testing with many different riders, 18.5% of the distance from the top of the femur to the floor in bare feet should be the crank length. You can find the top of the femur pretty easily. It's 5" to 6" below your hip bone, and moves rearward when you raise your knee."

 

See also: www.billbostoncycles.com/crank_length.htm

[xak1]

Saw an article once on crank lengths used by ProTour riders in TDF.  They change to longer cranks on mountain stages (where high cadence is not as important), and shorter cranks on flat stages.  My opinion is that your body compensates quickly for the difference, so one should not be too phased about this.  A 3% difference in torque can easily be cancelled by lower cadence, and a myriad of other factors.  Choose the crank and seat height which are forgiving on your knees.