These are really nice bib tights ( also have Assos and Giro bib tights). These bibs utilzie an excellent stretch fabric with good compression, very good breathablity, and a really nice chamois. I really appreciate the very comfortable chamois--the thickness, structure, and density works really well for me. I generally wear these tights from the low 30s to low/mid 40s and they peform extremely well without overheating. I wear the Storm + knickers from the low 40s to high 40s/low 50s. Sizing: I am @ 175 lbs, 33" waist, 32" inseam, and 40R chest. I have several size large bib shorts and a pair of knickers from Pactimo..and the fit of these size large tights is the same.