Off-road trip with some Rivian engineers

SwampNut · Jul 19, 2025

The head of the off-road engineering and some others put on a short trip and some lessons. Nothing like learning from the people who made your truck! I'll edit and post some video later, there are conversations I need to be careful with as I don't know what things they would want repeated publicly. I also got full answers on the question about the brake pedal moving in adaptive cruise.

Rivian R1T R1S Off-road trip with some Rivian engineers 1752976137202-g1

Rivian R1T R1S Off-road trip with some Rivian engineers photo-1839_singular_display_fullPictur

Rivian R1T R1S Off-road trip with some Rivian engineers dji_fly_20250719_072218_0016_1752935077063_photo

Rivian R1T R1S Off-road trip with some Rivian engineers IMG_7428

Rivian R1T R1S Off-road trip with some Rivian engineers dji_fly_20250719_085816_0020_1752942065051_photo

Rivian R1T R1S Off-road trip with some Rivian engineers dji_fly_20250719_085942_0025_1752942063553_photo

Drone video:

SeaGeo · Jul 19, 2025

Did you have to NDA? If not, you should be free to share info. They know what they're doing.

shrink · Jul 19, 2025

Where in the metro Phoenix area was this and why wasn’t I invited?

Polar · Jul 19, 2025

Compass Yellow Represent!!

love how you’ve got the CarPlay screen; hope some employees saw that

SwampNut · Jul 19, 2025

Polar said:
Compass Yellow Represent!!

love how you’ve got the CarPlay screen; hope some employees saw that

And a Comma self driving unit, removed for the off-roading. They saw both. I took a Gen2 LE quad for a joyride too, and talked to the sales guy about both of them. He is also a bit unhappy with having to repeat BS excuses for no CarPlay, and had never heard of Comma. He has a Tesla so he knows that Rivian is behind Autopilot for the most part.

shrink said:
Where in the metro Phoenix area was this and why wasn’t I invited?

Butcher Jones, by Saguaro, and Wassym said to use more deodorant...

This is the first one ever, and there will be more. Another will be done in the same spot "within a few months" and will have more invitations/publicity. CA will be next after that. They did a great job with it all around.

SeaGeo said:
Did you have to NDA? If not, you should be free to share info. They know what they're doing.

Nothing in writing, but in a personal conversation I was asked to trim things that were said in conversation that might not be officially "speakable." I am certainly going to respect that. Like I said, this is a first, to let the engineers go ride around and talk to owners with no marketing/legal people to filter anything. I want to be sure that doesn't get stepped on. Also there was a lot of general goofing that some low-humor people might find "unprofessional."

They had an official video/photo person with a drone so I'm sure we will get something directly from Rivian soon.

SeaGeo · Jul 19, 2025

SwampNut said:
Nothing in writing, but in a personal conversation I was asked to trim things that were said in conversation that might not be officially "speakable." I

I appreciate that.

SwampNut · Jul 20, 2025

It was clear in all the conversations that these guys are fully in it for the love of the challenge, as much as the dollars/job. I could see the excitement when I shared what friends and I have discovered that the Rivian can do, and many of us have spent a lot of time in high-dollar dedicated off-road toys.

zefram47 · Jul 20, 2025

SwampNut said:
It was clear in all the conversations that these guys are fully in it for the love of the challenge, as much as the dollars/job. I could see the excitement when I shared what friends and I have discovered that the Rivian can do, and many of us have spent a lot of time in high-dollar dedicated off-road toys.

Did you get any sense that they were still working on tuning the Gen1 Quad drivetrain in off-road situations (or for that matter low-mu on-road)? It certainly improved since I bought mine, but I wind up running dedicated winter tires due to its penchant for stepping out the rear in low-mu, off-camber situations. Off-road is similar, think mud or lifting wheels on rocks and not delivering torque to wheels that actually have grip. I'm sure we'd all still love to have a sort of virtual locker that just increased torque and limited wheels speed to something reasonable like 1-5 mph (as other manufacturers do for off-road crawl/cruise control).

SwampNut · Jul 20, 2025

zefram47 said:
Did you get any sense that they were still working on tuning the Gen1 Quad drivetrain in off-road situations (or for that matter low-mu on-road)?

I felt that it's mostly done. They said they learned things from gen 2 that were carried over, but there were no hints of further tuning. The conversations were past tense. I personally believe they are done with gen 1. That is my opinion based on a few conversations about things like tank/kick turn (which he showed off). Oh, and when a Rivian engineer says on the trail, "Hold on I want to try something." You should start rolling video.

I don't know what you mean about virtual locker, since that's what I perceive to be going on with the gen 1 dual already. It was effective, though the quads obviously did much better in slippery uphills.

SeaGeo · Jul 20, 2025

zefram47 said:
It certainly improved since I bought mine, but I wind up running dedicated winter tires due to its penchant for stepping out the rear in low-mu, off-camber situations. Off-road is similar, think mud or lifting wheels on rocks and not delivering torque to wheels that actually have grip.

I think that behavior is going to be present for any system where two motors are on the same axle.

They have better low end torque control with the Rivian motors, so I expect people will experience less of that behavior in the Gen2 quad (and tri) because of the greater level of precision at the low end.

zefram47 · Jul 21, 2025

SwampNut said:
I don't know what you mean about virtual locker, since that's what I perceive to be going on with the gen 1 dual already. It was effective, though the quads obviously did much better in slippery uphills.

I'm not sure how GM and Tesla implemented theirs, but I'm talking about virtual locking through motor control, not using the brakes as they do on the dual motor. Since you can drive or retard each motor/wheel individually, you can basically target matching wheel speed between any number of wheels. My profile pic shows a situation where I was flying the front-left and the rear-right was on loose soil, so very low-mu on two wheels and two with relatively high-mu. The only way to get the vehicle to move was to punch the throttle quickly and much more than you would with an ICE vehicle with a torque-converter and then back off quickly once it started moving. The issue is you're tippy on two wheels and it's not really safe to be applying that much torque that quickly. If you slowly apply throttle as you would with ICE, you wind up with your foot on the floor, the truck not moving at all, and eventually you get in turtle mode and have to let motors/inverters cool off.

My notion of a virtual locker would allow torque demand to increase on any given motor to either match speed with any other wheel/motor and allow a max of 1-5 mph of wheel speed to keep it relatively safe for the half-shafts. But without the driver needing to punch the throttle and hope to get something moving and back off before something bad happens.

SwampNut · Jul 21, 2025

Mine keeps climbing as you described. I’ve never had it back off or lose power, so I can’t envision what you’re saying. maybe it’s something that have added since then? We had a few similar situations on this drive and you could see the quads doing it better than the dual.

2kwik4u · Jul 21, 2025

zefram47 said:
I'm not sure how GM and Tesla implemented theirs, but I'm talking about virtual locking through motor control, not using the brakes as they do on the dual motor. Since you can drive or retard each motor/wheel individually, you can basically target matching wheel speed between any number of wheels. My profile pic shows a situation where I was flying the front-left and the rear-right was on loose soil, so very low-mu on two wheels and two with relatively high-mu. The only way to get the vehicle to move was to punch the throttle quickly and much more than you would with an ICE vehicle with a torque-converter and then back off quickly once it started moving. The issue is you're tippy on two wheels and it's not really safe to be applying that much torque that quickly. If you slowly apply throttle as you would with ICE, you wind up with your foot on the floor, the truck not moving at all, and eventually you get in turtle mode and have to let motors/inverters cool off.

My notion of a virtual locker would allow torque demand to increase on any given motor to either match speed with any other wheel/motor and allow a max of 1-5 mph of wheel speed to keep it relatively safe for the half-shafts. But without the driver needing to punch the throttle and hope to get something moving and back off before something bad happens.

I wonder if in this situation you are sneaking up on the torque capacity of a single motor trying to move the vehicle. The dual motors, while having less TOTAL torque than the quads, have higher stall torque per axle than the quads, and with the ability to brake one wheel you can effectively divert most of that torque to the wheel with traction. Thus landing in a situation where you can apply more torque to a single wheel.

Gen 1 Quad has 908ft-lb. Divided by 4 is 227ft-lb/wheel.
Gen 1 Dual has 829lb-ft. Divided by 2 is 414ft-lb/axle.......which used with brake biasing traction control is over 80% more torque available to a single wheel.

I took my dual offroading back in April. Captured this interesting video where you can see the front wheel spinning while completely unloaded, and the truck just pulled away as if I was driving on dry pavement, despite having two opposite corner wheels VERY unloaded.

Start around the 0:43 marker: https://photos.app.goo.gl/GDhJ4K5vzs28LDC47

2kwik4u · Jul 21, 2025

SwampNut said:
Mine keeps climbing as you described. I’ve never had it back off or lose power, so I can’t envision what you’re saying. maybe it’s something that have added since then? We had a few similar situations on this drive and you could see the quads doing it better than the dual.

There are a couple reviews online that talk about this. I've watched both OutOfSpec and TFLTruck discuss how an oddly loaded quad would "stall" on a climb and have to be "punched" to get the truck moving, then immediately back off to keep from rocketing ahead. I'll try to dig them up.

Could also be that these issues have been "tuned out" between when they had them, and now.

In other thoughts......What are these things?!?!

Rivian R1T R1S Off-road trip with some Rivian engineers 1753112517719-vs

MountainBikeDude · Jul 21, 2025

zefram47 said:
I'm not sure how GM and Tesla implemented theirs, but I'm talking about virtual locking through motor control, not using the brakes as they do on the dual motor. Since you can drive or retard each motor/wheel individually, you can basically target matching wheel speed between any number of wheels. My profile pic shows a situation where I was flying the front-left and the rear-right was on loose soil, so very low-mu on two wheels and two with relatively high-mu. The only way to get the vehicle to move was to punch the throttle quickly and much more than you would with an ICE vehicle with a torque-converter and then back off quickly once it started moving. The issue is you're tippy on two wheels and it's not really safe to be applying that much torque that quickly. If you slowly apply throttle as you would with ICE, you wind up with your foot on the floor, the truck not moving at all, and eventually you get in turtle mode and have to let motors/inverters cool off.

My notion of a virtual locker would allow torque demand to increase on any given motor to either match speed with any other wheel/motor and allow a max of 1-5 mph of wheel speed to keep it relatively safe for the half-shafts. But without the driver needing to punch the throttle and hope to get something moving and back off before something bad happens.

Tesla employed a mechanical locker on the single motor axle drives. On the Cyberbeast, it uses a physical locker on the front, which is really the only one you can lock via the UI if i'm not mistaken, and then just motor control on the rear virtually.

In comparing R1 quad to an unlocked CB, the quad still outperforms on motor control, maybe not so much on stall torque. When the CB or CT Dual is physically locked (front on CB, front and rear on Dual) the CT will not necessarily out perform a Gen 1 Quad, but it will induce less wheel spin/slipping because it has at least one axle that is locked mechanically maintaining a constant wheel speed, compensating for the virtually locked dual motor axle.

In the E-G Wagon, it employs a virtual locker on the 4 motors, but has the advantage of a per motor low range gear box, which eliminates the stall torque problems, and reduces the likelihood of one wheel spinning out.

Rivian patented a bolt on transfer case, but that hasn't seen the light of day. I would assume because they addressed stall torque in the Gen 1 Quad's with the new Ascent motors.
https://www.rivianforums.com/forum/...rawler-gearbox-bolt-on-for-off-roading.12461/

Off-road trip with some Rivian engineers

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