You've almost certainly heard the term, "free speed" bandied about in regard to aerodynamically-designed products. We're not sure "free" is exactly a proper term, after all, you have to buy the equipment, however, you do have to wear shorts too, so you might as well wear something that's going to help you go faster with less effort. Semantics aside, the concept of a component providing a speed advantage via design isn't new, but its application to clothing is somewhat newer, and the Free Aero Race 4 Short from Castelli is a perfect example. Its Forza fabric on inner legs with 38% Lycra content offers a perfect fit and since it's built for racing, it receives somewhat minimalist construction, but one that's made for aerodynamics and also comfort. Vortex dimpled fabric on legs boost aero performance while its updated Progetto X2 Air Seamless insert features one of the softest surface we've ever felt in a chamois.