So I understand that pain in the knees is usually due to a too-low or too-high seat, and with some fiddling I confirmed this. However, this happens to me even if I am really pushing myself by riding on a high gear (let's say, 3-5 out of a max 3-7), requiring me to stand to really get gravity and leverage involved -- my knees give out long, long before my quads/calves do. What am I doing wrong? I love to push myself as hard as I can, but maybe doing that somehow has the same effect as sitting down with improper seat height.
Could it be handlebar height? If they are too low, would the knee thing happen?
Let me know if you require more info. I am riding an admittedly crappy mountain bike, but all my biking is on pavement at the moment.