2019-05-15: Winter Biking (slightly updated 2019-12-27)
I've been winter biking for years, starting seriously in Thunder Bay, when I bought my first winter-beater bike (a 40-pounder CCM unsuspended 'mountain bike' - those were the days - 2000-2001): while it was cold, there is nothing like riding through 15-20cm of fresh powder on the trails under a full moon.
Through trial and error I've refined my tools and practice, as below: take it as you will.
Make it a beater, not your summer bike. Despite the efforts below, it
takes a toll on the bike overall: cut your losses. Don't make it a
cheap bike (like my original CCM), as you want moderately reliable
components - my suggestion is to keep your last MTB or hybrid. Yes, I'm
biased to more hardy frames/wheels/components, because winter. However,
I use a former hardtail, as I do mostly urban winter riding, and got
rid of the front shocks, because the salt eats them away. One time I
took the winter bike in for service, Ed at Liberty Cyclery wouldn't let me ride away
because the front shocks were so gone with a season of salt decay.
Another time they wouldn't let me ride home because the front bearings
were so far gone. They're good people, and I highly recommend them.
Brakes: No real preference. If it's really slippery, you can have too much brake. I've never run out of brake using rim or disc, as long as they were decent components and maintained.
Tires: I rode on Nokia studded tires in Thunder Bay in 2000-2001, and kept them in Hamilton. Once I hit Toronto they were old and kept blowing out when I hopped a curb (always from Parkside to the trail nroth of the Queensway west into High Park). I never replaced them - iIn the urban south, the roads are cleared by equipment and traffic, and that's where I ride. When there is the occasional heavy snow of +10cm, the streeters realiabley cut through the snow to the asphalt, unless they hit the packed snow of bus and car tracks. In the really cold winters of 2014-2015 and 2013-2014 there was pretty serious hardpack on the sideroads and some stretches of the arterials, but even then they were rideable, albeit cautiously. It seems to be a pattern that I stay upright until I slow down to a crawl, and have dropped more than once turning into our driveway playing it extra-cautious. Go hell-bent for leather, I say.
Drivetrain: When it gets really cold, odd things happen. Below -18 to -20 C or so, the grease on your freehub may start getting too thick to engage or disengage, meaning that you may end up with no engage at all, getting you nowhere fast, or a temporary fixie. While I was able to temporarily fix my usual no-engage problem by storing the bike inside, after 10-15 minutes of riding, the grease got cold and you were back to square one. The operable solution is to maintain continuous pressure on the pedals/drivetrain, both stop and go: an aquired skill, motivated by the desire not to walk the rest of the way. If you have a fixie all of a sudden, just keep pedaling - at least it's a fixie with gears so you can play with cadence. Outside of that, keep your shifters relatively clean, and related to cables below, at the end of your rides, leave the gears at the low end of the spring range (typically, the small ring/low gear at the front and small ring/high gear at the back): if your gears freeze up, being able to push-through the iced cable/derailleur with the shifter is pretty easy, compared to forcing/kicking the derailleur to free them up so the spring returns them to home position.
Cables: You want to keep them lubed, but they'll still freeze up with moisture penetration. As above on the drivetrain, at the end of the ride it's best to leave the gears at the low end of the spring range (typically, the small ring at the front and back): if your cables freeze up, being able to push-through iced cable/derailleur with the shifter is pretty easy, compared to forcing/kicking the derailleur to free them up sp the spring returns them to home position. If you have cable brakes, you can usually push through the freeze-ups well enough on first-use. I haven't encountered any problems with hydraulics.
Hands: Having gone through a hypothermic episode, my hands get cold fast and don't warm up quickly. I've tried really warm gloves, and my better half bought me great ones that keep my hands pretty warm but not easy to articulate or do fine motor work due to the glove thickness, and once they're off after getting heated up for a ride, I can't get them back on after locking up the bike: a problem at -20C. I found my miracle in pogies: hard or floppy handlebar mounts that you slip your relatively lightly gloved hands into for the ride. They cut out the windchill, which is the killer, while your mid-range winter gloves keep the hands warm and give you the precision you need to perform pre- and post-ride actovities (locking and packing, for example). The floppy ones Mountain Equipment Coop sell have a short learning curve, but they work - the stiff ones (also called bar-mitts, or some varient) are good from what I hear, but have a high price point and haven't reached my need-index, yet. A buddy of mind bought the motorcycle equivalent and found them effective, but I haven't explored that option myself. The pogies are handy in that they're soft enough, you can use the thumb-shifters and brakes from the outside as well, if you haven't got time to slide your hands in.
Feet: Like hands, my feet cool quickly and I found a couple of good fixes. Mountain Equipment Coop sold, stopped sellling, then resumed selling boot-covers - not foamy ones for the roadies, but a basic nylon shell that wraps around your shoe, velcro's at the back, and leave the bottem open for cleats. Brilliant - stops major wet outside of monsoon conditions, and even then lets you start out feeling moderately comfortable. It looks like they paused selling them for safety concerns - bit of a learning curve - and now they come in a back replete with saftey instructions (and annoying stra[ tensioners that I cut off). The other tech is gortex outer socks that I've used for decades - again, in monsoon they don't stop it all, but most, and leave you comfortable for the first 30 minutes. Beyond that, the ride heats you up, and makes you look forward to the closing shower. Beyond that, I have winter boots, and summer shoes.
Face: I alway wear a Respro Techno gold mask / air filter, warm or cold. In the cold, it takes care of wind-chill. In the warmer weather, it's there. Below 5C, being bald, I wear a breathable cap. Below -10C or so i wear a neck warmer. That's about it.
Body: Layers. Just build them up. If it's really wet, I'll go for the full gortex.
Riding: Sensible is the way to go, right? If it's slippy, slow down. Straight line? Fill your boots. Slow down for the corners and curves. Just be sensible. On occasion the trails get covered by drifts and even I will dismount and walk - theres's no shame in that. Also, try alternative routes, even the roads. On that note,when those 10cm+ situations arrive, feel free to skip the slippy bike lanes and take the road lane: cars will be moving slowly enough as is (unless they're in a big hurry to reach the next red light, at which point you'll have caught up with them. Give them a wave of appreciation).
Snow: Meh, it is what it is. Being in the south, and in an urban environment, it's pretty contained and manageable with road tires (not slicks). I haven't found much advantage with knobbies. I've never ridden fat bikes, so have no observation other than that tyring to ride snow machine trails with studded knobbies was unsuccessful in Thunder Bay. YMMV.
Avoid. Studded tires are good for solid ice or hard pack, but even in
Thunder Bay I
didn't run into much of that - though once is enough, particularly
when going too hot into a turn (though if it's cold enough for serious
ice, odds are there's enough snow, and it can make for a nice
slide, preferably into a snow bank). Still, on studded tires in TB I
dropped going through a turn (yes, too fast into a turn, and into a
snow bank, but I hit the solid before I slid into the snow) and broke a
Slush: I haven't encountered serious slush in the south, but in my northern Ontario biking experience, the ploughing doesn't start until the snowing has stopped ('cos all the cars have winter tires, right?), and it can be a serious control challenge due to their semi-solid nature and depth of 20-30 cm. Kind of like spring skiiing, it's granular, so an unusual texture that you can adapt to, but is out of the ordinary - doable, but a good work out. In the south, slush tends to be very brief and much wetter, at the late stage of the heavy snowfall: the most serious element isn't ride control but avoiding being slushed by passing cars, particuarly as they're shifting lanes when passing you. In general, more uncomfortable and inconvenient than a riding hazard.
Bike Spa: After a week or two of winter riding in wet conditions, the winter bike can be suffering. I'll treat this by giving it a power-wash, and drying it for a day or two in the basement before giving it a good lube on all moving and threaded parts, plus cables. Power-wash in the sub-zero can be fun,so leave it in in the low spring range/high gear on the back allowing you to gear up on the way home before the cables and component freeze (or just start out by leaving them in the high range and lug it home). Park it in the basement to let it dry, and lube. However, danger lurks. Powerwashing the cassette can let water penetrate into the rear components, including the freehub, and leave you spinning. So, sometimes it's better just to lube the bike and accept that it's winter, the bike will look grungy, and aesthetics of a clean bike sometimes lose out to functionality: trust me, I've been there, spinning on a clean bike with a frozen freehub.