Snow Mode--still too much regenerative braking

[atebit]

Net-net, it seems like Rivian should publish some guidance on this; to the OP’s point, best practice seems to be counter intuitive to (insert your facotor) decades of driving experience.

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[Bullwinkle]

That'd be my guess as well. I wonder if regen ABS is superior to friction brake ABS in super-low traction situations? Heck, I wonder what regen "ABS" feels like.

exactly my questions

 

[BeYrslf]

Picking up an R1T this week - have a Tesla Model S where the brake regen performs better on ice than the friction brakes as long as the battery is preconditioned IMO. Will be interesting to see how the truck does and compares. Tesla feels like its taking regen from all 4 wheels.

 

[Bullwinkle]

Picking up an R1T this week - have a Tesla Model S where the brake regen performs better on ice than the friction brakes as long as the battery is preconditioned IMO. Will be interesting to see how the truck does and compares. Tesla feels like its taking regen from all 4 wheels.

It is good to know that rapid regen modulation is possible, if you remember, do report back.

 

[emoore]

There are millions of Tesla's out there in snowy areas. Is this a problem with them too? Maybe it is and I'm just not on Tesla forums to find out.

 

[beatle]

For better or worse, Teslas don't have the same regen strength so they are less likely to overwhelm the available traction when slowing down.

 

[HyperionMark]

For better or worse, Teslas don't have the same regen strength so they are less likely to overwhelm the available traction when slowing down.

This isn't accurate. I've owned 3 Tesla's and now a Rivian(still own a Y). Rivian is barely more regen. Almost the same.

 

[beatle]

This isn't accurate. I've owned 3 Tesla's and now a Rivian(still own a Y). Rivian is barely more regen. Almost the same.

Both of my Model S (2015 and 2019) had weaker regen than the Rivian. The 2015 was the weakest.

 

[HyperionMark]

Both of my Model S (2015 and 2019) had weaker regen than the Rivian. The 2015 was the weakest.

Our X has the worst. The 3 and the Y were about as strong as the Rivian.

 

[HyperionMark]

Very slick roads here today and just went and verified there is indeed ABS style braking on regen as well. It stopped very quickly on just Conserve mode (which only uses the front axle). The ABS/stability icon even came up on the screen when it slowed down. I did not touch the friction brakes at all and I don't have it set to blend. You won't notice a sound like you are used to for regular friction ABS.

 

[Dave Cundiff]

A prior poster in this thread said that in Snow Mode, all the regenerative braking is in the front, impairing our ability to slow down and steer simultaneously. At least in my 2023 DM Max R1S, this appears to be mostly incorrect.

When regenerating in Snow Mode, the R1S' four-wheel dynamic image shows all four wheels involved with propulsion and regeneration, with maybe 54% of the propulsion or regeneration in the front axle and maybe 46% in the rear axle (if the bars in the graphics are indeed proportional to the propulsive or regenerative energy transfer).

I'll check how our 2023 QM Large R1T handles deceleration in Snow Mode. That might be similar or different -- I'll know soon.

***

Knowing what I now know about snow driving, I think I'd prefer to keep a slight excess of propulsion power in the front wheels (maybe 55% front to 45% rear, to help pull the vehicle uphill while tracking with the steering), while switching more regeneration power to the rear wheels (maybe a ratio of 60% rear to 40% front, to minimize front wheel sliding). Rivian could do this via an OTA, I think, if it turns out to be a good idea.

What do others think?

 

[HyperionMark]

Ya, so much bad info in this thread it's kinda crazy.

 

[HaveBlue]

I'd be worried if the rears don't do anything since it's the only axle rated for chains/cables.

 

[Bullwinkle]

Very slick roads here today and just went and verified there is indeed ABS style braking on regen as well. It stopped very quickly on just Conserve mode (which only uses the front axle). The ABS/stability icon even came up on the screen when it slowed down. I did not touch the friction brakes at all and I don't have it set to blend. You won't notice a sound like you are used to for regular friction ABS.

That is great info, I did not know there was an ABS icon. Makes me feel better.

 

[Bullwinkle]

A prior poster in this thread said that in Snow Mode, all the regenerative braking is in the front, impairing our ability to slow down and steer simultaneously. At least in my 2023 DM Max R1S, this appears to be mostly incorrect.

When regenerating in Snow Mode, the R1S' four-wheel dynamic image shows all four wheels involved with propulsion and regeneration, with maybe 54% of the propulsion or regeneration in the front axle and maybe 46% in the rear axle (if the bars in the graphics are indeed proportional to the propulsive or regenerative energy transfer).

I'll check how our 2023 QM Large R1T handles deceleration in Snow Mode. That might be similar or different -- I'll know soon.

***

Knowing what I now know about snow driving, I think I'd prefer to keep a slight excess of propulsion power in the front wheels (maybe 55% front to 45% rear, to help pull the vehicle uphill while tracking with the steering), while switching more regeneration power to the rear wheels (maybe a ratio of 60% rear to 40% front, to minimize front wheel sliding). Rivian could do this via an OTA, I think, if it turns out to be a good idea.

What do others think?

Many cars have discs in front and drums in the rear, so I think a front bias is typical.

My physics 101 professor let a toy car roll down a tilted table. It rolled straight and true. Then he used a rubber band to to lock the plastic rear wheels that easily slid on the table--the car slid off kilter. Then he locked up the front wheels and it slid true again. Counter intuitive for sure.

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