Our Cold Weather King, Anthony, provided these 6 tips to keep you warm in the winter while you're riding your bike!
1: Protect Yourself Before You Wreck Yourself
Solid Gloves, Socks, Balaclava for your head, ears. Your extremities are the first thing that will get hella cold, and frostbite is no fun.
Base Layer (Long Johns), Mid Layer (Fleece shirt and lined riding tights) Outer Layer (Jacket, pants, etc.) The idea is that you can keep warm, but if you get too warm you can always strip off a layer.
3: Windproof/Wetproof Material Should Always Be Your Jam!
You want to find gear that prevents wind from getting in and sweat from passing through. We all love the touch and feel of cotton because it is the fabric of our lives. However, avoid it all costs! It gets wet, and the fun is instantly over. Clothing with wool or synthetic wicking materials tends to be your best option.
4: Save Your Butt, Rock Fenders
Biking while wet is bad enough. Biking while wet, dirty, and full of salt and other foul shit that seeps into the stagnant road slush is downright unhealthy. You don’t want that stuff on you, and fenders are a guaranteed way to keep it that way. Also, no one likes a wet, frozen butt. If you do decide to install a more permanent fender, remember to always check for ice and snow build-up, or it can pack in between your wheels and the fender, and never makes for fun riding.
5: Traction Is Your Best Friend
I used to roll a little slower in the winter. Icy conditions or even a packed down snow can create slick patches where you least expect it. Most road bikes are going to have a slick tire, and during the winter that is just not going to cut it. I would recommend something with tread or even studded tires. I also had my tires set up with a lower PSI (not below the minimum recommended) to create more surface area that hit the road.
Pro Tip: You should run your rear at slightly higher PSI then the front since the majority of the rider weight will be over the rear
6: Clean Yo Shit!
During the winter, the roads are full of nasty junk, most of which are significantly damaging for a bicycle. Melting salt speeds up oxidization, rusting your bike faster, and the sand will get into the nooks and crannies and grind away at all the moving parts. You won't need to do a full clean every time, but running through your bike and wiping it down after riding it going to be massively beneficial.
Side Note: A single-speed / fixed gear is going to be a lot easier to clean than a geared bike. There are fewer parts to clean, fewer places for crude to get into and easier overall to maintain.