I own several Castelli bib shorts and several jerseys. Generally I find them excellent. These socks, however, run very small. I bought size L/XL, per the size chart. I wear an 8 1/2 size shoe. When I tried to pull the socks on they ripped up the side. Tried the other one and it ripped too. I don't believe I used excessive force or was careless, especially when I tried to pull on the second one, but the socks were very tight. I should have returned them but didn't want to put up with the hassle.
The socks are quite comfortable, once they're on. They are a tight fit, however, and even though they are right and left foot specific, they are hard for me to get on. Maybe my difficulties are age related, but I think anyone would have a bit of a struggle getting these on. Once on, though, they do a great job of keeping the feet cool.