3 ms·

I can certainly appreciate the "doesn't surprise me" aspect, but I still don't see how AWD / 4WD will help you when braking. It's obvious that it'll help when

I can certainly appreciate the "doesn't surprise me" aspect, but I still don't see how AWD / 4WD will help you when braking. It's obvious that it'll help when accelerating, and perhaps even when turning, with a (more) even application of torque on all wheels. My main gripe with it is that it often gives drivers a false sense of security (as they got going easily), and they'll drive too fast for the conditions. Just look at some parts of this sub-thread, where people say "I don't need winter tires, I have AWD / 4WD". If you need to brake in an emergency on snow / slush / ice, nothing is going to help you except your tires (and perhaps some smart ABS).

sliken 6y ago
Well, good ABS is hard. Having locked differentials can make the most of a really messy situation. Thus the reason for locked differentials (for going or stopping). There's a wide variety of software solutions as well, some work better than others. It's a non trivial problem. For instance. In normal conditions less braking when any wheel slips is best. In slippery conditions for stopping or going some slipping is best. In really messy conditions it can be best to not keep applying torque (in the positive or negative direction) without any "smarts". For emergency braking in the snow it can be best to just lock them up and have snow build up in front of the tires. To see an example of how big a difference this makes, check out https://www.consumerreports.org/video/view/cars/auto-test-track/4503044972001/awd-showdown-subaru-forester-vs-honda-cr-v-vs-toyota-rav4/ https://www.consumerreports.org/video/view/cars/auto-test-tr... I agree that AWD leads to overconfidence to some, I've been driving at 35 mph on the highway (with a 65 limit) in my Subaru (with good tires) in bad conditions and had giant SUV blast past me at 10-20 mph over what I was doing ... only to find them in a snow bank later. Doesn't mean that AWD wasn't a huge help. My first AWD was a result of me spinning out in a FWD around lake tahoe in poor conditions, in heavy traffic, at 10 mph or so. My front right tire lost traction, the open front differential put all power to the front right tire, and it spun me into a snow bank (just 18" away") in a blink. I was quite impressed how much rotational acceleration could happen in a blink of an eye. The open differential meant I was basically 1 wheel drive (when slippery), the car I replaced it with (Subaru WRX) had 3 wheel drive (when slippery) and was MUCH more predictable. In fact sliding in the snow would bring a smile to my face... and I changed my weekly commute (6 7200 foot passes) to maximize the snow involved. And yes I'd MUCH rather have all seasons and AWD instead of snow tires and FWD. It's not the ultimate traction as much as being predictable. Sure all seasons have less traction, but it's way more predictable and gives much better control when sliding. FWD, even with snow tires can be very unpredictable, and can easily spin a car when the traction is low. Subaru + snow tires seemed overkill for the roads I was on. Sure Subaru + all seasons might be safe in some conditions at 35 mph, snow tires might raise that to 40 or 45 mph, but FWD regardless of tires would mean much less, and Caltrans would require the pain of installing and uninstalling chains and worries about chain failures and/or damage to the car. Even with all seasons, my main fear with a Subaru (I've had two) is hitting enough snow to life the tires off the ground.

sliken 6y ago

Well, good ABS is hard. Having locked differentials can make the most of a really messy situation. Thus the reason for locked differentials (for going or stopping). There's a wide variety of software solutions as well, some work better than others. It's a non trivial problem. For instance. In normal conditions less braking when any wheel slips is best. In slippery conditions for stopping or going some slipping is best. In really messy conditions it can be best to not keep applying torque (in the positive or negative direction) without any "smarts". For emergency braking in the snow it can be best to just lock them up and have snow build up in front of the tires. To see an example of how big a difference this makes, check out https://www.consumerreports.org/video/view/cars/auto-test-track/4503044972001/awd-showdown-subaru-forester-vs-honda-cr-v-vs-toyota-rav4/ https://www.consumerreports.org/video/view/cars/auto-test-tr... I agree that AWD leads to overconfidence to some, I've been driving at 35 mph on the highway (with a 65 limit) in my Subaru (with good tires) in bad conditions and had giant SUV blast past me at 10-20 mph over what I was doing ... only to find them in a snow bank later. Doesn't mean that AWD wasn't a huge help. My first AWD was a result of me spinning out in a FWD around lake tahoe in poor conditions, in heavy traffic, at 10 mph or so. My front right tire lost traction, the open front differential put all power to the front right tire, and it spun me into a snow bank (just 18" away") in a blink. I was quite impressed how much rotational acceleration could happen in a blink of an eye. The open differential meant I was basically 1 wheel drive (when slippery), the car I replaced it with (Subaru WRX) had 3 wheel drive (when slippery) and was MUCH more predictable. In fact sliding in the snow would bring a smile to my face... and I changed my weekly commute (6 7200 foot passes) to maximize the snow involved. And yes I'd MUCH rather have all seasons and AWD instead of snow tires and FWD. It's not the ultimate traction as much as being predictable. Sure all seasons have less traction, but it's way more predictable and gives much better control when sliding. FWD, even with snow tires can be very unpredictable, and can easily spin a car when the traction is low. Subaru + snow tires seemed overkill for the roads I was on. Sure Subaru + all seasons might be safe in some conditions at 35 mph, snow tires might raise that to 40 or 45 mph, but FWD regardless of tires would mean much less, and Caltrans would require the pain of installing and uninstalling chains and worries about chain failures and/or damage to the car. Even with all seasons, my main fear with a Subaru (I've had two) is hitting enough snow to life the tires off the ground.