patellofemoral syndrome pain

[OakLeaf]

Crankarm length for me was just, 22 years ago I read somewhere that I should have 165s, so when I built up my race bike, that's what I put on. The difference from the 170s on my touring bike was obvious right away, and I never had another cycling-related knee flareup.

It has as much to do with your tibia/femur ratio (which can't be measured very accurately without an X-ray) as it does with the length of your whole leg, but a good fitter should check the angle of your knee at the top and the bottom of your pedal stroke. Set the seat height based on the angle at the bottom, then choose cranks short enough that your knees aren't excessively flexed at the top.

An added bonus is that it's much easier to spin smoothly with shorter cranks.

My knees feel it right away when my cleats are off by even a little bit, so that's one thing I don't need a fitter for. I wonder, if you feel your cleats are too far forward though, if the problem isn't actually that your seat is too far forward? Unless you have VERY long toes (and mine are pretty darn long), there should be enough adjustment to let you get the cleat under the ball of your foot. But maybe your knee is actually forward of the pedal spindle (which would also cause excessive flexion), and that's what you're feeling?