I was going to start a separate thread on a similar issue, but since this is here I'll just jump in, with apologies to OP.
Originally Posted by Brian DeGennaro
You may have to pronate more than most in order to not topple over while squatting. People with long legs will have their femurs shoot their hips way back past their area of base, which creates a large forward lean in order to keep the bar in the area of base. to compensate you are gonna have to turn your feet out more than most.
This probably describes very close to what I suspect my problem is. I'm fairly tall (6'3") and have monkey limbs. As a note, I used to squat horribly before fairly recently being exposed to the proper technique. Nonetheless, when I squat my toes seem to point further outward (both feet), especially when I put more force on heels since I have less friction created in feet due to smaller contact area w/ the floor. In my case, the sheer spot seems to happen at my knees, which is not good (I feel pressure toward the inside of my knees, as they don't bow out in proportion to my toes).
I have to do as Brian D described - put my butt way back and my chest pretty far down in order to remain balanced and with the bar above mid foot w/o stressing knees. Any advise or ideas here? I saw glute stretches mentioned earlier, but I'm not sure if this is the case if the area of stress is at my knees.