Mountain Biking - Crank Size

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Freerider
04-27-02, 07:16 AM
When I posted my thread on Kona Bikes, Kevin G Posted an image of his bike. I noticed the crank at the back was very small, much smaller then mine. Is that normal with Kona bikes??also is it possible to chnage the crank sizeon my bike.:confused:

MichaelW
04-27-02, 08:26 AM
Most bikes come with 170mm (for road) or 175mm (for mtb) whatever the size of the rider. Clearly this is wrong, since a 4'8" rider needs smaller cranks than a leggy 6'6" rider.
Many fitting guides completely ignore crank size, but it is the starting point for setting up a bike.
The large manufacturers limit their range to 165-175mm. Other crank makers provide a fuller range from 140 to 190mm.
More info at

http://www.peterwhitecycles.com/fitting.htm
http://simon.trinhall.cam.ac.uk/bike/cranks.html
a2psyklnut
04-29-02, 08:11 AM
I noticed the crank at the back was very small, much smaller then mine.

Crank at the back of the bike? What are you talking about? Do you mean where the pedals are, or the gears (cassette) at the rear wheel?

Regardless, in addition to different rider sizes, different uses require different length cranks.

For example, Downhillers and Slalom use shorter cranks for better clearance. Single Speeders use longer cranks for more leverage...etc.

L8R