For several years, I've worn Assos T.Cento_s7 bib shorts for any ride longer than 90 minutes. They have served me well for distances well over 150 miles, whether on pavement or gravel. I think the advantage of these bibs is that the chamois extends to the legs without any seams between the middle and the edge. A lot of chamois have seams where the crotch meets the legs and I tend to get hot spots at those seams.