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Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 10:27 a.m.

long post ahoy.

A long-time friend of mine is an off-road instructor, and a good one. He does work with Ford and Toyota as well as teaching private clients. And for the past few years, he's been training Rivian employees in off-road driving. From what I can tell, he was involved in some early testing (he's talked about overheating inverters on certain surfaces) but now Rivian is sending him groups of staff to learn how their vehicles work and what off-road driving really is. It's a three day course that involves a lot of recovery as well as driving techniques. Bill let me sit in on part of class #67.

I didn't get to talk to all the students, but we had a powertrain software engineer, a platform engineer, a testing engineer ("I come up with failure modes and the engineers have to figure out how to make the truck fail gracefully"), a field tech, an advanced concepts designer and one more. There was some very valuable cross-pollination going on. The rear suspension creaked. The software engineer wanted to know what that noise was, and then what a "bushing" is. The field tech wanted to get underneath to check the rear trailing arm. At our next stop, the two of them were under the truck doing a little show and tell.

The truck itself is a production-spec R1T "Launch Edition" that is on loan from Rivian and has over 5000 miles of off-road use on it from what I could glean. It's stock other than a bunch of recovery/safety gear and some Cooper off-road tires in the stock size - the Scorpion sidewalls are a little vulnerable for our environment. We also had a modified 4Runner with open diffs (because you learn more with open diffs) and a Range Rover Classic that has been in use by the school for decades. I didn't get to drive, I rode along all day as we wandered around the OHV area in the desert. Surfaces included packed dirt, sand, steep climbs, extremely tight gullies and a number of articulation-testing sections. The next two days were going to be on rock with a number of fairly big ledges. The purpose of the day was to teach students, not test the truck.

How did it do? In short, extremely well. The truck has four motors, which means the torque delivered to each wheel can be adjusted and it can make maximum use of each contact patch. Bill was wondering about a "locker" emulator where the rear wheels would be rotated at the same speed, but that may not be necessary. The thing that impressed me was the traction on loose (not sandy) climbs. There was no sign of any intervention, just smooth traction.

The four wheel independent suspension meant the Rivian didn't have the articulation of the Range Rover, but with the four wheel torque vectoring it wasn't that big a deal to hang a wheel from a drive standpoint. You still had less contact patch, but at least you didn't have a spinning wheel in the air.

A few pics to keep your attention.

Note the smooth underbelly. That's good for aero, but pretty useful for off-road. Also, note factory sliders.

Only treated with the greatest respect.

Now for more detail....

freetors
freetors Reader
8/24/22 10:34 a.m.

The engineers for the new bronco could definitely learn a thing or two about making things fail gracefully in an off road setting... Even minor faults can totally eliminate the use of four wheel drive.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 10:40 a.m.

Gotta love EV AC. It was near 100F when we were doing this, and we were all comfortable. Apparently the front seats are also ventilated but I was in the back :) Lots of room for me and a lot of stuff, even with David the big tech (seen above) in front of me.

Like a lot of new vehicles, the Rivian is covered in cameras. The most useful one for off-roading is one on the nose, because it can see over a crest before the driver can. The others were less useful for this purpose.

Part of the course included driving down a very tight little wash that had us three-wheeling around tight corners. The front corners of the Rivian with its stumpy nose are easy to place when you're up against a dirt wall. The 136" wheelbase, on the other hand, was a handicap. That's a full three feet longer than the one on the Rover. According to the instructor, the R1S has a 14" shorter wheelbase and is friendlier on the trail. He feels it has more feel on the steering - lots of talk about cutting down the level of assist to add to more feel.

The thing can take some good side slopes. We were at pretty close to 45* a few times and the Rivian was showing no signs of instability. I didn't document the actual angle (I didn't get my level app going on my phone until later) but it was impressive. Especially since all the driving was being done by novices.

Approach angle is very good. Departure angle less so but there's nothing to catch a dragging tail so it was almost never a problem.

The truck has multiple ride heights. We were in "HIGH" the whole time, leaving "HIGHEST" off the table. The reason is because it's an air suspension, and air suspensions let you have the perfect ride height or the perfect spring rate, but never both. HIGHEST means too much air pressure and the ride quality and flex suffers badly. 

There are also different drive modes. There's a general off-road which they use most of the time. There's a Rock Crawl mode that remaps the accelerator, makes the torque vectoring more aggressive and limits top speed to 20 mph along with limiting maximum torque delivery. It apparently also affects the damping but I didn't get technical details. We had to go into Sand Mode once on a very loose climb, where the limited torque delivery of Rock Crawl meant we just didn't have all the power we needed. That also puts you in HIGHEST ride height and we could tell the difference immediately.

Regen is amazingly strong. A lot more than I expected. There's a "Hold" setting that applies the friction brakes when you stop so you can one-pedal most offroad driving, but we had it turned off because apparently the release is not quite as smooth/predictable as the instructors would like. Regen won't bring you to a full stop, nor will it hold back the truck on a steep descent. But it's pretty effective. There were times when turning the regen down to a lower level (all part of the settings) would have allowed for smoother driving, but we also had EV novices driving so they weren't used to the way an EV will brake hard when you lift.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 10:41 a.m.
freetors said:

The engineers for the new bronco could definitely learn a thing or two about making things fail gracefully in an off road setting... Even minor faults can totally eliminate the use of four wheel drive.

The instructor in the Rivian is heading to Michigan next week to keep working on Broncos, actually. Did you know they have a one-pedal emulation mode?

bmw88rider
bmw88rider GRM+ Memberand UberDork
8/24/22 10:42 a.m.

I saw some of the video that they did for the support of one of the motorcycle adventures and it looked like a really good package. It would do everything I would need a truck to do. Now if the price wasn't so eye-watering, I'd be in. 

mtn
mtn MegaDork
8/24/22 10:51 a.m.

On the street, one pedal driving is 100% possible. You don't even need to put it in park! 

This reminded me of one thing that I liked, and one thing that I didn't: I loved the big infotainment screen with easy access to literally everything, from the ride height and suspension settings, to the radio and HVAC, to closing the charging door and frunk. But one thing that I really missed is having a knob for the radio. I want to be able to turn the radio on, off, volume up, volume down, with a single knob, and preferably another one for tuning. 

 

My buddy showed me how to raise and lower the ride height and switch between all the different modes. He told me that I could go anywhere and do anything with it offroading, I would not be able to get in trouble. I didn't have any time to do any, because we don't have any good spots around us and I'm a complete novice, but still pretty impressive that he was that confident in its abilities. 

 

Keith, did the instructor show you the tank turn? Or is that not possible in production vehicles?

 

RevRico
RevRico UltimaDork
8/24/22 10:57 a.m.

No mud or snow though, much more relevant to my local area, once the price comes down about 90%. 

Still, good to see that it's as competent as expected, even in the hands of novices. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 11:00 a.m.

Now for some of the real fun. Bill started guiding the trucks through a wash crossing that looked pretty gnarly to me. That's because this is a recovery class as much as anything else, so getting stuff stuck was allowed. Here's the RRC getting pulled out - we'd used the maxtrax on the Toyota. No cheating with the air lockers, that would not have illustrated the point.

Now it was time for the Rivian. This was the only time I wasn't in the truck, so it's the only video I got. Remember, this is a driver who had not been offroad until earlier that day, and he was probably the worst one there. He made the fatal mistake of allowing it to stop when the rear wheels dropped and the belly landed on the dirt.

 

We tried raising it from HIGH ride height to HIGHEST and that didn't make any difference. So we strapped it to the Range Rover because it's heavier than the 4Runner. Remember, the Rivian weighs 7000 lbs. We used a kinetic recovery strap to help.

No budge. So we strapped the Toyota to the Rangie and played tug of war again. 

 

We learned later that the driver of the Rivian had also found that he couldn't get enough drive with full throttle in Rock Crawl mode, so he'd switched to Sand Mode for that second attempt. Apparently a recent software update had remapped the Rock Crawl throttle and our instructor was unaware of how much until a coworker confirmed it.

Over the course of the entire day - about 4-5 hours of constant wheeling with the AC on full blast  - we used about 35 miles of range. It was telling that the school didn't even bother having a full charge in the truck at the start of the day. I did learn that if you're running sand mode to get out of stuff, you're burning up battery very quickly because of heat management problems.

Overall, the Rivian is quite capable for a full size truck offroad. Very comfortable and the instructors couldn't say enough good things about the four motor torque vectoring. However, it's still a full size truck with the weight and length that entails. The independent suspension does make it a bit more of a challenge to keep the wheels on the ground than a stick axle vehicle, as you'd expect.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 11:03 a.m.
RevRico said:

No mud or snow though, much more relevant to my local area, once the price comes down about 90%. 

Still, good to see that it's as competent as expected, even in the hands of novices. 

Mud and snow is difficult to arrange in the desert in August, alas. And this was a school, not a test. The team certainly had mud experience with the truck and we were discussing how you'd drive differently for snow - less regen, for example.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 11:03 a.m.

I don't know if the tank turn made it into production. It wasn't really relevant for the day.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 11:06 a.m.

Only the greatest respect.

iansane
iansane Dork
8/24/22 11:29 a.m.

Insightful. Thanks for sharing that with us. Looks like fun.

I think Dirtfish rally school and a local car club have put on similar recovery/4x4 novice knowledge events which looked interesting. Makes me want to attend. Wonder if they'll scoff at the 2wd e30truck.

engiekev
engiekev HalfDork
8/24/22 11:31 a.m.

Very interested in this!  Recovery of a Hummer EV is going to be no joke.

Robbie (Forum Supporter)
Robbie (Forum Supporter) GRM+ Memberand MegaDork
8/24/22 11:36 a.m.

Sweet

STM317
STM317 PowerDork
8/24/22 11:45 a.m.
Keith Tanner said: we were discussing how you'd drive differently for snow - less regen, for example.

What's the thinking here? I'd think that the linearity of regen braking would be beneficial in snow.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 11:59 a.m.
STM317 said:
Keith Tanner said: we were discussing how you'd drive differently for snow - less regen, for example.

What's the thinking here? I'd think that the linearity of regen braking would be beneficial in snow.

It's basically remapping the braking torque the same way you can remap the acceleration torque. Make the regen less aggressive and it's easier to manage the traction levels and avoid breaking traction. You could feel a similar behavior on the dirt surfaces - the area had almost a crust on it, so once you exceeded a certain amount of traction the surface would shear and become loose. A driver who was abrupt with the regen could easily cross that threshold and you'd feel the vehicle start to ooze down the fall line slightly. A smoother driver would stay within the traction limits. Making the regen less aggressive just makes it easier to toe that line.

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 12:08 p.m.
mtn said:

On the street, one pedal driving is 100% possible. You don't even need to put it in park! 

This reminded me of one thing that I liked, and one thing that I didn't: I loved the big infotainment screen with easy access to literally everything, from the ride height and suspension settings, to the radio and HVAC, to closing the charging door and frunk. But one thing that I really missed is having a knob for the radio. I want to be able to turn the radio on, off, volume up, volume down, with a single knob, and preferably another one for tuning. 

A knob for tuning a radio, you're showing your age :) We did have a situation where the Rivian decided it wanted to listen to the local public radio station and there was some discussion about "why can't you just turn it off?". Making the radio stop was more involved than it had to be. ND Miata owners have the same problem, you can mute but there's no "off" - at least they have a physical volume/mute button. Since radios (audio systems) are now part of the always-on car computer, the concept of turning it off is a little arbitrary.

You could certainly one-pedal drive right to a stop on the flatter sections of the trails, but the slopes tend to be a little steeper than you find in, say, Seattle.

One comment that this picture reminded me of - flat bottomed steering wheels are ok on the street but were not great for the trail, and that elicited some comments. The driver here was not shuffle steering as much as the instructor would have liked him to.

I forgot to mention, the Rivian had a moment after that extraction. It wasn't happy, couldn't get itself combobulated for drive mode or ride height for a minute. It was fairly upset with us. Also, Sand Mode comes with a bunch of warnings, it's fairly clearly intended for short term use only. I didn't get a chance to read them all because the instructor was running the screen and he knows the car well so he was quick to dismiss them.

It also had a tendency to leave the interior lights over the rear doors turned on when the front doors were opened and closed again.

codrus (Forum Supporter)
codrus (Forum Supporter) GRM+ Memberand PowerDork
8/24/22 12:17 p.m.
Keith Tanner said:

A knob for tuning a radio, you're showing your age :) We did have a situation where the Rivian decided it wanted to listen to the local public radio station and there was some discussion about "why can't you just turn it off?". Making the radio stop was more involved than it had to be. ND Miata owners have the same problem, you can mute but there's no "off" - at least they have a physical volume/mute button. Since radios (audio systems) are now part of the always-on car computer, the concept of turning it off is a little arbitrary.

<rant>

Pretty much all cars have this problem these days.  I get that there isn't an "off", but I don't understand why it's so difficult to have a "I don't want any music" mode.  Pause is fine, but it needs to REMEMBER that you paused it and not automatically unpause when you restart the car.

<end rant>

The battery consumption numbers are interesting.  I wouldn't have expected it beforehand, but thinking about it now it makes sense -- most of the power goes to making the car move down the road, not to just being "in use", and the lack of an idling engine really helps there. 

 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 12:34 p.m.

An ND Miata will allow you to easily mute (push the volume button) but not pause. That's really inconvenient if you're listening to audiobooks, for example. You can patch that in software but it's a weird oversight on the part of the engineers.

One of the students asked about offroad energy consumption and the instructor pointed out that a lot of it came down to driving style. But good offroad driving looks a lot like hypermiling, because you're trying to avoid abrupt speed changes which are expensive from an energy point of view. I don't know how far we actually traveled, but actual ground speed when moving was in the mid-to-high single digits and we were moving most of the time until we got to the recovery portion.

There were some jokes about "quiet electric vehicles" as we stood around the Rivian with the AC system roaring away.

californiamilleghia
californiamilleghia UltraDork
8/24/22 12:42 p.m.

Great report , 

I think battery use is mostly pushing the box down the road at speed , 

what you were doing takes only a little battery per hour , 

did you do any tests going in reverse ?   Did it know not to dig a big hole with the rear tires ?

 

mtn
mtn MegaDork
8/24/22 12:43 p.m.

My wife also found the flat bottom of the steering wheel annoying. I noticed it, and thought it would be bad for a performance situation, but had no complaints with it for daily driving. 

As for showing my age, us early 30 year olds are an annoying segment of the Millenials for sure.

ProDarwin
ProDarwin MegaDork
8/24/22 1:01 p.m.

Thanks for sharing Keith.  Pretty cool. 

codrus (Forum Supporter) said:
Keith Tanner said:

A knob for tuning a radio, you're showing your age :) We did have a situation where the Rivian decided it wanted to listen to the local public radio station and there was some discussion about "why can't you just turn it off?". Making the radio stop was more involved than it had to be. ND Miata owners have the same problem, you can mute but there's no "off" - at least they have a physical volume/mute button. Since radios (audio systems) are now part of the always-on car computer, the concept of turning it off is a little arbitrary.

<rant>

Pretty much all cars have this problem these days.  I get that there isn't an "off", but I don't understand why it's so difficult to have a "I don't want any music" mode.  Pause is fine, but it needs to REMEMBER that you paused it and not automatically unpause when you restart the car.

<end rant>

<rant>

My Kia has bluetooth, but zero control over it from the radio, so even pausing stuff cant be done.  Thankfully I can use the *knob* to turn it down/off/switch inputs, but in some cases the audio will keep playing on the phone, so its annoying.  Also if you are playing from the USB input or a CD, there is no pause button.

<end rant>

<rant 2>

If I pause Audible on my phone, but have google maps on, as soon as google maps gives any voice command, it will unpause Audible.  I can repause, but at the next command it unpauses it again.

</rant 2>

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 1:02 p.m.
californiamilleghia said:

Great report , 

I think battery use is mostly pushing the box down the road at speed , 

what you were doing takes only a little battery per hour , 

did you do any tests going in reverse ?   Did it know not to dig a big hole with the rear tires ?

 

By "tests in reverse", do you mean "did we try to back the truck out when it was stuck"? Answer is yes, we tried. It was flat on the belly and was very comfortable in its hole. 

There were definitely talks about the traction control being reactive. It has to spin the wheels to know they're spinning. The school would have preferred something more proactive, like a locker. It does apparently take steering angle and suspension height into account - a fully extended corner is going to have less traction than a fully compressed one. But when you're sitting on the belly and all four wheels are extended the same amount, the computer really doesn't have much to work with.

thatsnowinnebago
thatsnowinnebago GRM+ Memberand UberDork
8/24/22 2:37 p.m.

Gotta love seeing the front bumper smack the side of that ditch, just before the truck got stuck. I knew it was coming but I still cringed. Seems to came out relatively unscathed though. 

I tell my wife that I'll quit my job and just do something for fun when she starts pulling down huge money (a guy can dream right?). Off-road instructor is now high on that list. I bet everyone had a blast that day. 

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
8/24/22 8:40 p.m.

It was fun reading the instructor as things got a little dodgy. He was very calm and got calmer as things were slowly going wrong. It's like instructing on track but in slow motion. I did notice that Bill's Range Rover might have some slightly modified side panels but a pristine roof, so apparently keeping things the right way up is a core competency. But you would not want to be a nervous person in his place.

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