Cold-weather riding: ice, cold tyres and numb fingers
Corner Speed splits cold-weather riding into three limits. A road that can freeze is the only absolute one.
3 min readBy PitPin Desk
The Corner Speed blog published a guide to winter riding on 4 November. It answers "how cold is too cold?" with three limits.
Ice is the hard limit
A road surface that can freeze stops the ride. Below an air temperature of about 3 °C, bridges, shaded bends and dips can already be at or below freezing, especially early in the morning after a clear night. The road is often coldest just after sunrise and can be frozen while the bike's dashboard still shows 3 °C.
Ice rarely covers a whole road. Bridges and overpasses freeze first because cold air reaches them from above and below. Shaded bends and stretches under trees stay frozen for hours after the sun has dried the rest. Water running across the road from field drains or melting snow can freeze into a clear sheet that looks just like wet asphalt. On borderline days the guide suggests riding in the afternoon, when the surface is warmest.
Cold tyres are a temporary limit
Tyres warm up from load: braking, accelerating and cornering flex the carcass. Weaving on a straight road adds very little heat. Rider sources quoted in the guide suggest 10 to 20 minutes of moderate riding before a street tyre is up to temperature in the cold, and longer for sport compounds. Until then, keep lean moderate and braking gradual.
The heat goes again when you stop. A 20-minute coffee break in cold weather takes much of it out, so the first bends after a stop need the same care as the first bends of the day. Pressure also drops by roughly 0.1 bar for every 6 °C, so tyres set in a warm garage will be low on a cold road. Check them cold, at outside temperature.
Wind chill and numb fingers
Wind chill on a bike comes mostly from your own speed. Using the Environment Canada wind chill formula, a 5 °C day feels like about −1 °C on bare skin at 50 km/h and about −3 °C at 100 km/h. Most of the drop has happened by town speeds, so slowing down adds little warmth. Covering the gaps at the neck and wrists does more.
The guide cites dexterity research that puts a sharp drop in fine motor control at a finger skin temperature of around 15 °C. Progressive braking depends on a few millimetres of lever travel, and numb fingers cannot judge that. If your fingers go numb, stop and warm them up.
Before a winter ride
Rinse salt off with cold or lukewarm water after every ride on treated roads, then lube the chain again. A battery that was weak in October often fails on the first frosty morning, and heated gear adds to the load. Corner Speed suggests checking the voltage at the battery with everything switched on at a steady cruise: below about 13 volts, the bike is putting back less than you are using.