This was my first pair. A friend recommended them. I bought large first and realized immediately that I needed medium. Siroko makes it very easy to return items if you bought the wrong size. The medium came in a fit like a glove. I’m 6’ and 170lbs. Very lean. These are the first mediums I have bought. I would have to say they run big. I rode them on a 60 mile ride the other day. The only negative would be the chamois. I like a little thicker one. But still a very comfortable bib for those 3 hours. The bib straps are soft and wide so no digging into shoulders. These are good enough to possibly make me leave Castelli and The Black Bib. Well done Siroko!