I have 165mm on my full squish to help with pedal strikes and to see what it would do for my knees. My hardtail and road are still rocking 175mm cranks. The first time I rode the 165mm they felt funky for a couple mins ever since I can't tell even swapping back and forth. My knees feel roughly the same after a ride on all three but I do get less pedal strikes on the FS.