I don't see why people say to size up on this stuff. Castelli and other Euro brands are made for athletic people and they fit the measurements provided on their prospective websites. If you are overweight, order a size up but stick with the sizing chart. I wear a medium Castelli bib and I am 6 ft and weigh 165 lbs. The length of the bibs is tight walking, but once you get on the bike it is perfect.