I bought these bibs figuring I would want to change kits half way through the DAMn ride 243 miles. My buddy changed kits 3 times and at each stop I said no to my kit change. 243 miles in 16 hours and no chafing. Might be the best purchase of my life! I am on the upper end of the medium size. I bought medium and they were very tight and wished maybe I should have ordered a large, but now I'm happy I got the medium.