I ride my bike down to about -20C. Below that it just stops being fun for me. I ride a road bike on the road year round, and have tried to adjust my equipment to minimize drag while still being warm enough to make it the 12 miles to work (and then back again).
Feet
- Thick wool socks (sometimes two pairs) and insulated hiking boots (make sure the boots are a couple sizes too big so that the socks are not snug in the boots. Snug cuts off your circulation and makes you cold. This setup I run with studded flat pedals.
- 5 mm neoprene overshoes on top of my regular cycling shoes/socks. This setup is good to about -8C.
Legs
- Roubaix type material winter bib tights with a wind proof front over shorts is good down to around -5. Below that I add a thick pair of cross country skiing tights over top.
Chest
- Windshell outer layer (this is a size larger than I'd usually wear) in bright fluorescent green with lots of reflective patches (you're riding in the dark when it's cold).
- Synthetic fleece insulation layer. I have three different weights that are used depending on exactly how cold it is.
- Thick, long sleeved, cold water surfing rash guard as a base layer. This adds a surprising amount of insulation and warmth, dries quickly, and keeps your body feeling dry(ish)
- The chest area to me is the most important. If you can keep the chest warm enough, you can underdress the extremities and be OK. If the chest gets cold or chilled, you will have icky fingers/toes no matter how many gloves or how thick your boots are.
Hands
- Thin winter jogging gloves over a pair of thick ski gloves. The ski gloves give me enough dexterity to comfortably work brakes and gear levers. The thin gloves keep my hands from freezing while I have the thick gloves off to lock up/unlock. They also provide some insulation. Note - you have to buy these together. You want them to fit without being loose and definately without being tight. Tight stuff at the extremities cuts circulation and makes you cold.
Head
- I have an old helmet that I taped over the vents with some packing tape. This blocks wind flow and keeps your head surprisingly warm at the top.
- alternate between a thin windblocking ear band, a medium weight beanie, or both depending on temperatures.
Face
- When it's subzero always cover your face to protect from the wind and because re-breathing hot air from your lungs cools you off more slowly.
- I've got a couple heavy weight buffs, a neoprene half face mask, and a balaclava for this.
- Wear something over your eyes because the cold will make them water and ice/snow/hail stings (not to mention the crap they use to salt the roads). I have to wear glasses for nearsightedness so purchased a large lense clear pair from zenni specifically for cycling and use them. I find ski goggles tend to fog on me from the heat of cycling, but some swear by 'em.
Be aware, no matter what you put on your bike you will go slower when it's cold. Winds are usually more intense. Slippery conditions will require slower riding for safety. Snow and ice accumulate on you and your bike which weighs you down. You'll find it harder to catch your breath through face coverings, so will often be short air. The air itself actually becomes significantly more dense in the cold, so you'll just go slower. My average commute time ends up 15-20% slower in the cold months.
