On a Road Cycling, the baselayer sits directly under the jersey and determines your body temperature. It absorbs sweat and wicks it away to the outside, preventing you from getting chilled by the wind during descents.

The mid-layer keeps you warm on cold rides and wicks moisture away from your body. On a Road Cycling, it needs to fit snugly: every loose fold will slow you down and let cold air in.

The insulation provides warmth when your body can no longer generate it itself: at the top of a mountain pass, during a break, or after a breakdown on the side of the road. It packs down small and fits easily into a jersey pocket.

The top layer protects you from wind and rain, especially at the front of your Road Cycling where you're hit by the wind. It fits snugly, doesn't flap, and at the same time allows heat generated during climbs to escape.

On a Road Cycling, your shorts determine your comfort throughout the entire ride. They fit snugly without constricting, keep your muscles warm in the wind chill, and their length, from short to long, is adjusted to the temperature.