Q Factor and ankle to knee pain

[amartha]

I am currently converting my triple chain-ring gears to compact doubles. The triple chain-ring cranks being wider are causing me pain in my left ankle that sometimes shoots to the knee.

How does Q-factor affect forces upon the ankle? Does cleat position make it worse?

[sundial]

Here's an interesting read about Q factor/knee pain.

http://www.cptips.com/crnklth.htm

[amartha]

I've now completed several rides with the compact double. It shifts better than a triple and the left ankle is no longer causing pains that shoot to the knee. Some adjustments are necessary -- saddle position and cleat placement -- to eliminate other pains to the knees.

The width of the crank affects the angle of the foot to the pedal. I'm petite, and I have short shanks, so every adjustment is crucial. Longer legged riders, perhaps, aren't as affected by a few millimeters extra in the width of the crank.