R1T vs. R1S in snow?

[Jtg11]

Searched, but could not find anything. I own both R1T and R1S, both with 20” AT stock tires. I am about to head off on a trip in the snow. Does anyone have any experience or knowledge as to which model performs better in the snow. I suspect the R1T with the longer/wider wheel base, but really not sure.

Any thoughts?

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[R.I.P.]

Searched, but could not find anything. I own both R1T and R1S, both with 20” AT stock tires. I am about to head off on a trip in the snow. Does anyone have any experience or knowledge as to which model performs better in the snow. I suspect the R1T with the longer/wider wheel base, but really not sure.

Any thoughts?

DM performs better in the snow than QM does. Otherwise, yes, the difference is just going to be the wheelbase issue.

 

[Blackrock2014]

DM performs better in the snow than QM does. Otherwise, yes, the difference is just going to be the wheelbase issue.

I suspected this may be the case. Can you elaborate on that?

 

[Jtg11]

DM performs better in the snow than QM does. Otherwise, yes, the difference is just going to be the wheelbase issue.

Interesting on DM vs QM. Both my S and T are QM. This seems counter intuitive to me that the Dual would be better than the Quad … why would that be?

 

[R.I.P.]

I suspected this may be the case. Can you elaborate on that?

Sure. There are whole threads about it, but a differential offers inherent lateral vehicle stability because of the way it anchors the wheel with the most traction. To do this requires a physical connection between the wheels (the differential), so when the QM removed this, it also removed the inherent lateral stability of the vehicle. To be clear, this is not a Rivian issue, my Hummer EV had the exact same issue (in the rear) in snow, ice, and slippery stuff. The cyber truck (TriMotor) will suffer from the same problem.

Rivian has done much too minimize the problem with snow mode and good tires really help. But at the end of the day, the DM is just going to be much more laterally stable in really slick stuff.

 

[Phatman113]

DM performs better in the snow than QM does. Otherwise, yes, the difference is just going to be the wheelbase issue.

I would love to see the info behind this!

 

[R.I.P.]

I would love to see the info behind this!

There is much information available on the basics, but in my case i have owned both the QM and the DM, and have many thousands of miles off-road in both. As has been stated so many times, QM shines in some areas, but very slippery surfaces are not one of them, especially when you start introducing off camber situations.

Understand how a differential works to laterally anchor a slipping vehicle, and you will understand why getting rid of it is crippling in these scenarios.

 

[Jtg11]

There is much information available on the basics, but in my case i have owned both the QM and the DM, and have many thousands of miles off-road in both. As has been stated so many times, QM shines in some areas, but very slippery surfaces are not one of them, especially when you start introducing off camber situations.

Understand how a differential works to laterally anchor a slipping vehicle, and you will understand why getting rid of it is crippling in these scenarios.

Interesting! Thanks for the mini education.

 

[R.I.P.]

Follow up:

On an off-camber, slippery surface, it is helpful to focus on where is vehicle is _not_ trying to apply power rather than where the vehicle is trying to _apply_ power. By default, an open differential will always attempt to apply power (both "going" and "stopping") to only the wheels with the least traction on each axle. This is highly desirable when you want the wheels with the most traction to keep you from moving sideways, into a ditch or a tree, etc.

The QM has no option but to always at least attempt to apply power (both "going" and "stopping") to all four wheels, going into traction control mode when it senses slipping. Current software iterations have made behavior better, but the QM is always going to be working at a disadvantage attempting to overcome a problem the DM simply does not have.

 

[usofrob]

I suspect that dual motor isn't always better. I believe it's better for lateral stability to keep you from sliding off a cliff on your side. But what about going up a slippery hill? Seems like that would depend on how quick the stability control is as slowing the slipping wheel vs the motors doing it themselves.

What about driving around a snowy track?

Also, do you think Rivian could emulate a diff by only applying power at opposite corners? That way there would always be two tires that aren't slipping. A "No side slip start" type of mode.

I wonder if braking down a hill is actually better with DM as well, because the QM can't perfectly emulate free wheeling, so the regen will always cause more problems with QM than DM.

Also, back to the OP's original question, often times tires are the ultimate decider of more grip. If one of your vehicles has more tread depth, that might be the best one to take.

I did a "drag race" in the snow with my Lotus Elise with fresh Blizzak tires (open diff, no traction control) against my uncle's 4WD Chevy Avalanche (probably AT tires), and it was pretty even to about 30-40 mph where we let off.

 

[IGR]

I think the easiest way to think about it is that when 3 wheels lose traction on Quad-Motor the most power you would have available is 25% at the remaining wheel. Because lefts and rights are not connected.
While on Dual Motor, through engagement of traction control, you could get up to 50% of that power applied to the wheel with traction.
Lets assume there is a guy with g-wagon and all of his lockers are engaged, he would be able to put down 100% of available power to the wheel with traction.

How would that help in Snow? I am not sure, but it would be fun to test this theory.

 

[EVentually]

For anyone interested in Rivian's quad motor system and specifically how it compares to a locking diff, I highly recommend this article (with comments from the Principal Engineer of Rivian’s Drive System team). It was one of the reasons I placed a pre-order to begin with: https://jalopnik.com/a-ridiculously-detailed-look-at-why-the-rivian-r1t-elec-1847749837

 

[Dark-Fx]

T and S are pretty comparable on snow. Ultimately it comes down to whichever has the better tires.

 

[R.I.P.]

For anyone interested in Rivian's quad motor system and specifically how it compares to a locking diff, I highly recommend this article (with comments from the Principal Engineer of Rivian’s Drive System team). It was one of the reasons I placed a pre-order to begin with: https://jalopnik.com/a-ridiculously-detailed-look-at-why-the-rivian-r1t-elec-1847749837

The theories presented in this article are exactly why I bought a quad. I drank the Kool-Aid and asked for a second glass.

Then the real world happened. Simply stated, the QM doesn't begin to live up to its hype in real world off-road conditions.

I sold the QM, upgraded to a DM, and am much happier.
?

 

[sierraskier]

I suspect that dual motor isn't always better. I believe it's better for lateral stability to keep you from sliding off a cliff on your side. But what about going up a slippery hill? Seems like that would depend on how quick the stability control is as slowing the slipping wheel vs the motors doing it themselves.

What about driving around a snowy track?

Also, do you think Rivian could emulate a diff by only applying power at opposite corners? That way there would always be two tires that aren't slipping. A "No side slip start" type of mode.

I wonder if braking down a hill is actually better with DM as well, because the QM can't perfectly emulate free wheeling, so the regen will always cause more problems with QM than DM.

Also, back to the OP's original question, often times tires are the ultimate decider of more grip. If one of your vehicles has more tread depth, that might be the best one to take.

I did a "drag race" in the snow with my Lotus Elise with fresh Blizzak tires (open diff, no traction control) against my uncle's 4WD Chevy Avalanche (probably AT tires), and it was pretty even to about 30-40 mph where we let off.

Right. Maybe for the very specific use case of off camber ice the DM has an advantage over QM....but other than that, it's highly debatable and very dependent on the details of each scenario (deep snow, packed snow, ice, flat, incline, off camber, etc...) and most importantly...THE TIRES

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