I have ridden on 172.5 for the past 15 years without issue and when I built up my Lynskey last year, opted for 175's. After a full year of pain, I developed plantar faciitis and achillies tendonitis in both legs. Require surgery on one in the coming months. My surgeon, a very avid cyclist with a sports medicine clinic blames the spin diameter and over use directly. Take it for what its worth, just one guys experience.