The sorpasso is the ideal tight for a wide range of winter riding conditions but some areas are just too cold for the sorpasso so with the castelli sorpasso windstopper bib tight theyve taken everything you love about the sorpasso and added out thick fleecy windstopper x fast 2 fabric to the knee and thigh to extend the comfort range down to well below freezing but castelli have kept the thermoflex core due in the front around the seat pad area because they love the way this fabric offers go