Mos' def. I ride 42 x 16 and I intend to try a 40 tooth ring or 18 tooth cog. Your knees also might hurt because of poor pedal stroke. Not sure how you ride, but you should not mash so hard on the down stroke that you are still pushing down while the pedal is at the lower apex. You should have your foot pointed down and pushing backwards at that point. Going to a much lower gear will help you to better your pedal stroke because the high RPMs will make you spin out otherwise. So yeah, a lower gear and smoother stroke is best for the knees.