Rivian off-road struggling?

[Zybane]

Watched this video and didn't come away exactly impressed with the Rivian Off-Road. And it's a pretty easy trail they took.



Thoughts?

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[kylealden]

Lots of good discussion in this thread: [Video] Out of Spec: Hitting The Trails For The First Time This Year With A Rivian R1T, Frontier Pro-4X, & Lexus GX! | Rivian Forums - R1T & R1S Owners, News, Discussions, RIVN Stock

The tl;dr is that it's going to take getting used to. In this case the driver was babying it because he heard wheel spin, but with the way the power delivery works in the Rivian, he should have been adding more power and would probably have sailed right over, but it's unintuitive.

There are probably things the truck can and likely will do in software to get better at situations like this. For now, it's more "different" than "worse."

There's a reasonable case to be made that mechanical differentials and lockers would improve power delivery in some of these cases, but I'm not convinced Rivian needs it. It's plenty capable, just quirky relative to a conventional drivetrain.

 

[Mbxmikey]

Lots of good discussion in this thread: [Video] Out of Spec: Hitting The Trails For The First Time This Year With A Rivian R1T, Frontier Pro-4X, & Lexus GX! | Rivian Forums - R1T & R1S Owners, News, Discussions, RIVN Stock

The tl;dr is that it's going to take getting used to. In this case the driver was babying it because he heard wheel spin, but with the way the power delivery works in the Rivian, he should have been adding more power and would probably have sailed right over, but it's unintuitive.

There are probably things the truck can and likely will do in software to get better at situations like this. For now, it's more "different" than "worse."

There's a reasonable case to be made that mechanical differentials and lockers would improve power delivery in some of these cases, but I'm not convinced Rivian needs it. It's plenty capable, just quirky relative to a conventional drivetrain.

I concur completely. Rivian could easily add a locking feature in off-road mode. But I don’t think it very practical. It would be more of a gimmick like the tank turn. You can get all the same places with it or without it. It will just take some figuring out how the truck drives.

 

[Zybane]

No such thing as a locking differential in the Rivian setup. The two motors on each axle cannot be physically locked in any way. A "virtual axle" cannot use the power of the wheel's up in the air motor. So that one wheel that is touching the ground, still only has that one electric motors worth of power. No way to double the power in software using the driving power of the other motor that has the wheel in the air.

Hence why for off-roading, even in EV's, they will need mechanical lockers. And the reason I suspect that GM put a mechanical locking differential in the front of the Hummer EV.

I think Rivian's will struggle more off-road than people think. High weight plus limited power when in traction limited situations, especially on inclines, combined with "small" 34 inch tires with not that aggressive treat due to highway energy use restrictions.

 

[cardad]

The Out of Spec and TFL guys routinely come across as really bad, clueless drivers. Out of Spec Kyle recently included a scene of himself hooking up the air compressor on the Rivian to deflate his tires, which probably didn’t need to be deflated anyway. Then when he got back on the highway he claimed to inflate them to 49 psi.

 

[Davethadog]

The Out of Spec and TFL guys routinely come across as really bad, clueless drivers. Out of Spec Kyle recently included a scene of himself hooking up the air compressor on the Rivian to deflate his tires, which probably didn’t need to be deflated anyway. Then when he got back on the highway he claimed to inflate them to 49 psi.

I would use the compressor gauge if I didn’t have anything else on hand to get the tires to a safe low pressure.

 

[PoorPilot]

Maybe it's just me but I find these types of videos something my young kid would watch and think it's the end all, be all, without knowing anything else or asking questions. Within the first 3+ minutes, they're taking the steps off the Nissan and calling it a "rivet, bolt, allen-key wrenches, whatever you call them". I get it- they're creating videos for viewership, money, etc., but you should know what in the world you're talking about before making a 30min video talking about the pluses and minuses of certain vehicles. I couldn't get past more than a few minutes past the step issue.

 

[zipzag]

......................

I think Rivian's will struggle more off-road than people think. High weight plus limited power when in traction limited situations, especially on inclines, combined with "small" 34 inch tires with not that aggressive treat due to highway energy use restrictions.

I think that with high clearance and 4WD 99.9% of Rivian owners will do just fine on the back roads roads people actually travel with expensive vehicles.

The vast majority of people interested in back country travel are not going to be seeing which rocks they can climb over. Those that do are likely in their 20's and will quit after the $20K recovery and repair bill.

Anyone know where Kyle got the Nissan truck?

 

[SeaGeo]

Then when he got back on the highway he claimed to inflate them to 49 psi.

He inflated it to 49 because he had observed it tends to over report by 1 psi.

Which matches the recommended pressure from Rivian. So whats the complaint here?

 

[Zoidz]

As others have said, it seems to me it's more relearning how to drive the Rivian. The owner of the Rivian said that 3 or 4 times. The frequent comments in the video "Rivian need a locking diff" . No, not necessarily - rethink that comment. The purpose of the locking diff is to ensure that power is applied to the wheel with traction, instead of spinning the lofted wheel. Even with a lofted wheel. the Rivian *will still* have 200+ hp available at the tire with traction, unlike an open diff. A locking diff on a Rivian would apply up to 400 hp to that one wheel. DO you NEED 400 hp to one wheel? If you can't move with 200 hp, is 400 hp going to make a difference? At that point, you are risking spinning the tire on the rim and needing bead lockers.

I really didn't see anything disappointing with the Rivian.

 

[kurtlikevonnegut]

The best off-road vehicle ever made would look bad with that dude driving it. I only watched the first few minutes and all I could think was "damn dude give it some throttle."

Pretty sure he was in rock crawl too which means the throttle is mapped for a lot of pedal travel to get power delivery.

 

[cardad]

He inflated it to 49 because he had observed it tends to over report by 1 psi.

Which matches the recommended pressure from Rivian. So whats the complaint here?

Guess I forgot that this thing weighs 7400 lb … My 11k lb GVWR Winnebago RV takes 60-65 psi so I guess that sounds about right. You just don’t think of a Toyota Tacoma with 34” tires needing almost 50 psi.

 

[ajdelange]

So that one wheel that is touching the ground, still only has that one electric motors worth of power. No way to double the power in software using the driving power of the other motor that has the wheel in the air.

Recall that in a situation like the one being described it is not more power that is wanted but more torque. Each motor is connected to its own gear box. The torque limit is established by the motor and gearbox components. If you want to be able to send the torque available from the motor driving a spinning wheel to to other wheel you would have to be able to couple and uncouple the two gearboxes and increase the torque handing capacity of each. How often does this situation arise? How would you control it? What a kluge! I really don't see any way to justify it it terms of any realistic use case (certainly not the one in the video) but then I'm not very knowledgeable about off roading.

 

[rydb]

I’ve come to like out of spec a lot after watching all their rivian coverage. They aren’t into reshooting to fix when they misspeak in one of these videos, so you get that.

Definitely agree that there should be enough power to move the truck with 2 tires touching, so probably some further tweaking of the drive mode programming can improve this.

Somewhere it was mentioned that the real technical problem with the quad motors is the rate it which it samples and controls the wheel spin via throttling. It apparently will spin a 1/4 turn before the system knows it has broken traction. Hopefully they won’t need different hardware that samples the rotation of each motor/wheel quicker in order to really make this system work well.

 

[Dark-Fx]

Hence why for off-roading, even in EV's, they will need mechanical lockers. And the reason I suspect that GM put a mechanical locking differential in the front of the Hummer EV.

Hummer's front diff is locking because it's only a single motor and absolutely will just spin one loose tire if it doesn't use the brakes to lock the spinning wheel up. Rivian should make enough torque at each wheel independently to not need anything which will transfer power from one wheel to another.

I expect the issue is the person driving the truck just wasn't giving it enough pedal. You'd fail with the beefiest off-road vehicle if you weren't giving it enough throttle under certain conditions. The hard part with the Rivian is the lack of audible feedback that an ICE has.

Guess I forgot that this thing weighs 7400 lb … My 11k lb GVWR Winnebago RV takes 60-65 psi so I guess that sounds about right. You just don’t think of a Toyota Tacoma with 34” tires needing almost 50 psi.

The Hummer EV requires 45 psi in those giant tires because of its heft.

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