Thanks for the comments so far. I had terrible tendinosis for years which I'm recovering from, and the smaller cranks (172.5) really do help me keep my cadence up. With the 175mm cranks I had before, it was harder to pedal quickly and it seemed to put more force on my knee. BTW, seconds 30-40 are how I normally ride, the rest I was moving around to show the tops/drops, etc.