I have used various knee warmers under Mocean bike patrol pants, with long Smartwool socks as needed, but late last winter used Assos Roubaix bib knee-length tights for the first time, on a cold evening ride, and it was heavenly. I think I wore the Mocean pants over the Assos tights, but the Mocean pants are merely to keep wind out; they do not increase actual warmth. I should add the disclaimer that winter is not very cold here; the average January low temp is 40-ish.