My DH is on his 3rd day of riding the SI Turbomatic Gel Flow, and he is liking it more and more each ride. I can't even hazard a guess as to how wide his sit bones are...but prior to the Turbo, he was riding a 143 Toupe, and prior to that he was on a cheap Performance 130mm saddle. So apparently, he is one of those odd specimens that can ride ANY width saddle and be totally fine.