Yeah, I'm not sure why, but going clipless has been a godsend for my knees. Better pedal stroke, probably? (rounder). Also, I feel that I'm using a different set of muscles than before. I feel soreness (the good kind) in muscles in my upper legs I hadn't noticed before. I am not sure what any of it means, but the decreased knee discomfort has been the biggest plus in going clipless. All the efficiency, speed, power gains (if they exist) have been gravy...