I live in the frigid Canadian prairies and drive around BC, Alberta and Saskatchewan all the time in winter in the worst conditions. I'm now in my second winter with my M3 LR RWD and I'd have no worries at all about driving the Trans Canada route in winter once the Superchargers are all up and running reliably. There still seems to be some reports about them not working so I'd give it some time to have all the issues sorted out.
I have many, many years with lots of winter driving (hockey all over the prairies, downhill and cross-country skiing whenever I get the chance, visiting family) under my belt and have been in all sorts of horrid conditions. I learned to drive with a RWD car with bald tires before winter tires, ABS or traction control were even available. I would hesitate to recommend the drive to someone who hasn't much experience with winter driving though. If you do, I have a number of recommendations:
I have many, many years with lots of winter driving (hockey all over the prairies, downhill and cross-country skiing whenever I get the chance, visiting family) under my belt and have been in all sorts of horrid conditions. I learned to drive with a RWD car with bald tires before winter tires, ABS or traction control were even available. I would hesitate to recommend the drive to someone who hasn't much experience with winter driving though. If you do, I have a number of recommendations:
- Get good winter tires. There are roads in BC where they're mandatory and they're also mandatory in Quebec IIRC. I'm happy with Nokian Hakkapeliitta R3s on my LR RWD.
- There are many desolate stretches. Make sure you are prepared to survive on your own if you go off the road and there's no help for hours. Good winter clothes from head to toe should be available inside the car. Emergency food and water. Candles and matches can do a great job keeping the inside of a car warm. Snow shovel. Warm blanket.
- If you have someone you can check in with daily so they know you've completed your day's drive safely, that would be good.
- Alberta and BC have websites that are up to date for the road conditions. Check them and the weather forecast often. Better to spend a couple of days in a town waiting for the highways to be cleared (there's a reason they call Revelstoke "Revel-stuck") than stuck in a ditch somewhere waiting for a tow.
- Charging a cold battery sucks. I'd only stay in places where I could use an L2 charger overnight so I leave with a full battery. Now with the update that preconditions the battery if your Nav system has a Supercharger stop planned, it's far better than it was last winter (don't get me started...), but don't plan on getting a fast Supercharge on a cold battery with less than 1 hr of Hwy driving first.
- Best to top up at a Supercharger before arriving at your day's destination or stay where there's L2 charging than to hope to charge in the morning.
- If you leave the car outside and unplugged overnight, don't be surprised when in the morning you have 10-15% less battery charge than when you parked the night before. It happens.
- If you do plug into L1 (they're available all over for block heaters in places where it gets really cold) you likely won't get any additional range, or far less than you hoped for, but you'll also not likely lose any range either. Also, I've been fooled by these. Sometimes they're on timers or cycle on/off and that can cause some nasty surprises.
- I've been happy with TACC in winter. Helps me keep my speed down for conserving range, but I do turn it off when the roads are icy.
- Auto-steer does work far better than I'd have guessed. However, I prefer to take control to drive around icy patches, snow drifts, and to keep tires on dry pavement and off ice and rumble strips. Use with caution and due diligence.
- If you didn't already know - press the defrost button once, it turns blue and defrosts with the temperature your climate control system is set at. Press twice and it turns red and will blow hot air on the front windshield.
- The rear end is a magnet for salt/grime/snow. Clean your tail lights every chance you get. While you're at it, clean all the cameras, it keeps your car from nagging you as much.