VERY close call today on snowy/icy Interstate 40

[dsm363]

Anecdotal evidence. As a matter of fact, RWD (besides single wheel drive) is the worst type of drive-line to have for winter driving. For 2WD, front wheel drive is superior. Even though FWD is superior to RWD in winter conditions, they still both take quite a back seat to AWD.

Man this snow storm just won't quit, I hope I can make it home and I wish I had a RWD car! (Said no one ever with a brain)

That's all true but talk to people with AWD cars and all season tires. They seem to think they can drive on anything because the car is AWD.

 

[FlasherZ]

Did you feel the stability control kick in? When the car begins to slide sideways, the car begins to apply braking forces to individual wheels to get it straight again. If you're not used to it, you may be trying to counter it with the steering wheel.

 

[tinm]

OP - curious if you were in normal regen or low?

When I first picked up my D, it had normal, low and OFF for regen. Off disappeared sometime after. Odd. . . Off was absolutely where I felt I'd want to be in the snow.

At the time of this incident, I was in normal regen.

I started using low after this incident. But after 2.5 yrs of driving with normal regen, I find the low setting annoying :-/

- - - Updated - - -

Did you feel the stability control kick in? When the car begins to slide sideways, the car begins to apply braking forces to individual wheels to get it straight again. If you're not used to it, you may be trying to counter it with the steering wheel.

Assuming this question was for OP (moi)...

No, I felt no such stability control kicking in, nor were there any flashing icons in the driver's dash display. It felt like the rear end of the car was utterly out of control, no traction with the ground, and that I was about to lose the vehicle.

 

[AWDtsla]

No, I felt no such stability control kicking in, nor were there any flashing icons in the driver's dash display. It felt like the rear end of the car was utterly out of control, no traction with the ground, and that I was about to lose the vehicle.

I believe there is some level of activation before the indicator shows. Regardless, if regen didn't cut out immediately, then we know there's no support for moderating regen during stability control. Also stability control works by adding brake force, yet the car is _already_ applying brake force via regen. There's little it can do at this point.

 

[Electric700]

...

No, I felt no such stability control kicking in, nor were there any flashing icons in the driver's dash display. It felt like the rear end of the car was utterly out of control, no traction with the ground, and that I was about to lose the vehicle.

I'm glad you got through it, but I would think that your car should have detected the loss of traction. Consider contacting Tesla and ask them to review your car's logs and traction/stability control systems.

 

[tinm]

I'm glad you got through it, but I would think that your car should have detected the loss of traction. Consider contacting Tesla and ask them to review your car's logs and traction/stability control systems.

"Consider contacting Tesla" . . . heh. "Consider," fine. "Consider contacting," sure, so far so good. "Consider contacting Tesla," oh. You lost me at Tesla. It's too much work and not worth the effort. Communications are so awful with Tesla and (I suspect) triage is so high at Tesla that I just don't bother unless it's something not only I but Tesla would consider urgent.

 

[mspohr]

I believe there is some level of activation before the indicator shows. Regardless, if regen didn't cut out immediately, then we know there's no support for moderating regen during stability control. Also stability control works by adding brake force, yet the car is _already_ applying brake force via regen. There's little it can do at this point.

There has been a lot of speculation in this thread about how TC/SC/ABS works on ice and snow. The only people who really know how these systems work are the engineers who programmed them and they aren't talking.
However, we do have anecdotal experience of people here who have noted that AWD D cars are much better behaved than RWD cars (not just ice and snow but also rain and dry pavement). This is universal for ICE and BEV cars. We also have been told by Tesla/Elon that the car is capable of making adjustments to power many times a second. From this, I think we should conclude that the control systems of all Teslas take throttle, power, steering sensors, wheel sensors, acceleration sensors, etc. input and make constant adjustments to power (including regen) and brakes. I would be surprised if the car did not do this.
It should not be necessary to make any manual adjustments to regen since the car can (and most likely does) make these adjustments many times a second and does a much better job than any human could do of adjusting throttle, etc. It is really best to take the human out of the loop since he (mostly he) will most likely muck things up. (It would probably be best to even let the car take over steering since most people do not know how to steer through a skid and don't have the fast reflexes of the car control systems.)
As far as the poor performance of RWD cars on ice and snow goes... well, this is a RWD car and... physics!

 

[FlasherZ]

I can't tell you the exact programming of the ESC system, but I can tell you that when the car detects yaw, it begins applying brake force at the appropriate corners to straighten the car. It is not traction control, because it gets applied whether or not you've applied power to the wheels, whether or not traction control is turned off. When it's snowy outside, I like to take my car sideways across my driveway - because, well, it's fun. The Model S won't let me do that.

 

[bhzmark]

Perfectly fine to engage neutral to remove power with no application of regen which might brake too strongly. I do it all the time. It's flick of the wrist. Then you have only brake input through the brake pedal and applying to all 4 wheels instead just the rear in the case of rwd cars. This shld be especially useful to rwd cars.

 

[AWDtsla]

Relevant One year living with the BMW i3 - YouTube

 

[EarlyAdopter]

"Consider contacting Tesla" . . . heh. "Consider," fine. "Consider contacting," sure, so far so good. "Consider contacting Tesla," oh. You lost me at Tesla. It's too much work and not worth the effort. Communications are so awful with Tesla and (I suspect) triage is so high at Tesla that I just don't bother unless it's something not only I but Tesla would consider urgent.

The couple of times I've experienced something questionable with my car, my emails to servicehelpna@ have been taken very seriously and responded to immediately, including additional follow-up from my local service center. Give it a try. Very different set of folks and communications than elsewhere at Tesla, in my experience.

 

[mspohr]

Just a bit of real world anecdotal experience from today...
I drove my daughter to the airport (100 miles RT about half on I80) in my 85D today during a fairly heavy Sierra snowstorm. Road was packed snow and ice most of the way. Lots of cars off the edge and passed two multi-car accidents... it was slippery.
The car performed incredibly well. Steady, secure, solid the entire way. I took advantage of a few deserted stretches of the road to try some extreme acceleration and deceleration moves and while the little yellow "slippery" indicator lit up, the car stayed on the straight and narrow. I couldn't make it go sideways or feel a noticeable slip or slide.
Driver assistance features unavailable...
Very solid ride.
(Note: I have the factory Pirelli Sotozero snow tires which don't have the best reputation but they were great today.)

 

[AudubonB]

That's one angry-looking car! "Don't Mess With Tesla"

 

[electrish]

Looks more like a bearded Tesla!