Originally Posted by late
Glenghillie,
I have one leg longer than the other. I put a shim under the cleat of my road shoe. That helped a lot. Another option is custom length cranks.
Actually, these adjustments address two different issues. If the difference is mostly in the upper leg, then your pedal stroke will be different and, if it's great enough, different length crank arms would be in order. You would also want to set the cleat so that it puts the foot with the longer upper leg further forward.
If the difference is mostly in the lower leg, then the cleat shim for the shorter leg is in order.
I happen to have both. My legs are about the same length, but the left has a longer upper leg, shorter lower leg. So the left cleat is set to put my left foot further forward, and it's shimmed.