Past couple months have been putting in some good time on the bike, but noticed that i had pain in my left knee...took it easy for a week and it went away. Went out this weekend on a 35 mile loop and by mile 25, was having severe sharp pain in my right knee, tried standing more often, but that didn't help. So I figured it must be my seat positioning, as I have not changed it in some time.....set it forward a couple of millimeters and raised it a couple and I can't beleive the difference! No pain and I felt like hills I normally give good effort on were done with ease. And my overall pedaling seemed more efficient.