Wearing numerous layers of clothing to stay warm is, well, obvious. Feeling cold? Pull on an extra jersey; that’s what we all know works. For cycling, especially in cold weather, however, each layer is an integral part of a whole system. Cycling is a high-performance activity and correct clothing choice can enhance performance as easily as poor clothing can hamper it.
Why not make a jersey, for example, that does the whole thing in one go? It is possible and there may even be such a garment but such an approach lacks a certain flexibility; if it isn’t right for the conditions, there’s not too much that can be done. Windproof jackets tend to fall into this trap and, as a result, usually have a system of vents to help with heat management.
They work for many people and are one way to tackle winter cycling. The other is to layer up. To get the best effect, it is worth remembering the two fundamentals of staying warm: air insulates, while moisture cools. Fabrics trap air between their fibres; the more air that is trapped, the slower heat leaves the body. Being trapped, the air can’t move around and transfer heat from the body outwards through convection.
Wet fabrics not only conduct heat very effectively but, if given the chance to lose any excess moisture, cool through evaporation. Perhaps the easiest way to get very cold is to sweat profusely inside a waterproof shell and then remove it to allow vapour to steam away from soaked clothing.
So, wicking moisture away from the skin as it is sweated is important. So too is getting rid of moisture before it soaks clothing, although this is almost impossible in heavy rain. But for cold, dryish weather, dry clothing is best. How much ventilation is required to achieve this will vary from person to person.