Snow Mode fail - costly result

[Bullwinkle]

Damn, sorry to hear that OP.

I see a lot of people talking about no regen as the solution but I'd suggest that is not the right way to think about the problem. I have always used shifting into lower gears as a way to control my speed in ICE vehicles because it is less likely to cause a skid. Regen braking is the EV analogue, the problem is getting used to it and being much more deliberate with how you use your right foot. Never hard-lift off the throttle. Always roll-off, with the speed determined by the conditions. I don't mind Rivian offering a no regen option for folks, but I don't think no regen and all brakes is going to be safer unless you're unwilling to learn and use the one pedal driving technique.

To be fair, I think Rivian and other EV makers should do more to educate new EV owners about this type of thing. I've found it hard to retrain the muscle memory from ICE driving and in a situation like OP's I might have made the same mistake. I have actually practiced this on a snowy hill to get a feel for traction under regen but muscle memory takes time to retrain and sometimes you only have a split-second to decide how to react.

Down shifting and regen can be feathered, but they do not have the ability of ABS to keep the car going where it is pointed. When drivers have multiple cars at home, radically different inputs and behavior should not be required when traction is lost in an emergency situation...especially true with inexperienced drivers.

On real ice almost any amount of clutch or regen can induce a skid, and without the benefit of ABS. Feathering the clutch frequently certainly causes a lot of wear.

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[mkhuffman]

There is a difference between regen and 1PD.

Regen uses the motor to slow the vehicle, but it will not necessarily stop it. 1PD means the vehicle stops without the need to use the brake pedal. As the speed of the wheels slow with regen, the physical brakes are needed to bring it to a full shop and hold it there. I think this is what causes the wheels to lock up on low traction surfaces.

There should be a way to turn off 1PD. You can in my Mach-e and still have regen. The difference is the car slows with regen but the wheels never lock up if 1PD is turned off.

A couple others have suggested using neutral. I think that is a great idea. If you start to slide, instead of lifting your foot off the accelerator, flip it into neutral and use the ABS brakes lightly as needed.

Modulating the accelerator works great with 1PD, but when you start lose control, neutral may be the best option. Maybe even temporarily to get the wheels to unlock. And then flip it back to drive and modulate the accelerator again.

Someone should experiment.

 

[jemkewl]

Hey OP - long thread - do you have the regenerative breaking assist on or off?

I would think that could have a more significant impact than regen in certain situations.

 

[HaveBlue]

Haven't driven the dual motor variants, but under regen, don't the rear motors engage, especially under hard braking events? I know they re-couple above 35 mph? when the driver commands extra power, but curious if the same is true when braking/decelerating?

I have not experienced the rear motor ever kick back on in All Purpose in Regen mode. So if you are going down a curvy mountain road under regen, only the fronts brake and it understeers badly going into a corner. The rear will engage briefly if you give enough throttle.

 

[HaveBlue]

I think trimotor is actually AWD in all purpose and FWD in conserve but it has auto AWD like the dual motor all purpose.

You're right! They changed their EPA testing to remove the annoyance. It's why the EPA range is lower than the dual but probably the same if run in conserve.

 

[Zorg]

Down shifting and regen can be feathered, but they do not have the ability of ABS to keep the car going where it is pointed. When drivers have multiple cars at home, radically different inputs and behavior should not be required when traction is lost in an emergency situation...especially true with inexperienced drivers.

On real ice almost any amount of clutch or regen can induce a skid, and without the benefit of ABS. Feathering the clutch frequently certainly causes a lot of wear.

My experience is exactly the opposite in my quad motor R1T.

 

[Donald Stanfield]

The regen doesn’t bother me. I’ve driven through a few snowstorms and the stock tires are the bigger issue. If I lived somewhere with regular snow I’d get snow tires.

 

[LL75]

Is there no snow tire option without replacing wheels ?

Is there no snow tire option without replacing the wheels?

Nokian 275/55/22

 

[crewzer]

Are they decent ? Why do so many change the wheels too?

 

[White Rock Rivian]

Are they decent ? Why do so many change the wheels too?

I prefer the bigger sidewall of the 20 inch tires.

 

[TollKeeper]

I prefer the bigger sidewall of the 20 inch tires.

They do ride SO MUCH better than the 22"

 

[Seano]

Def sorry @TdsT : definitely miserable, but glad no injuries. As many have said - the tires are where its at. While none of us were there (same road, same conditions) with snow tires, I can only speak from experience here: night and day diff from all seasons to snows. Your situation and this thread bring up many concerns to keep in mind in the really bad weather and how we can adjust.

I run the Haka R5 SUV and do have 20" wheels with slightly larger sidewalls - I think this **may** add to grip, too, in the snow & ice. But I wouldn't hesitate to run these tires on 22s either. I'm impressed at how nicely these tires run on warm pavement down in the Bay Area (even though snows are supposed to be used below 40 degrees or so)

 

[Bullwinkle]

Def sorry @TdsT : definitely miserable, but glad no injuries. As many have said - the tires are where its at. While none of us were there (same road, same conditions) with snow tires, I can only speak from experience here: night and day diff from all seasons to snows. Your situation and this thread bring up many concerns to keep in mind in the really bad weather and how we can adjust.

I run the Haka R5 SUV and do have 20" wheels with slightly larger sidewalls - I think this **may** add to grip, too, in the snow & ice. But I wouldn't hesitate to run these tires on 22s either. I'm impressed at how nicely these tires run on warm pavement down in the Bay Area (even though snows are supposed to be used below 40 degrees or so)

I agree that snow tires--especially the Haka R5--would almost certainly have helped. Even an All Weather, 3-peak-snowflake tire is better than an AS tire. Ice sometimes happens in places with mild winters and sometimes happens outside of normal winter months.

With most issues in life, causation isn't singular. I think both tires and too much regen braking can be culprits that lead to accidents. Rivian needs to add a rgen defeat setting.

Non sequitur--add manual battery conditioning too.

 

[UnsungZero_OldTimeAdMan]

Maybe title should change to "costly user-error" @Administrator

 

[Bullwinkle]

Maybe title should change to "costly user-error" @Administrator

More likely the regen helped break the coefficient of friction.

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