The first versions of windproof/breathable jackets, in the early 1980s, were made of sweater-like synthetic material (or Italian wool) with nylon panels on the front of the torso and sleeves. The next generation had full nylon coverage on the front and back of the sleeves. Your arms don't generate enough heat while cycling to counteract the cooling effect of wind.
Last edited by Trakhak; 01-23-21 at 05:22 PM.