Does Stability "Off" really mean Off?

[1550nm]

I wrote my Guide this question, and wonder if the Forum can help resolve this issue:

Very Briefly
When the “Stability” setting is turned off, is traction control supposed to be off entirely or just reduced?

A bit more detail
There are 3 Stability settings in most drive modes (default, reduced & off). The names (and descriptions) should indicate the behavior in each setting, but that is NOT what I’ve experienced. Perhaps there is something I’m overlooking? That the setting is called “stability” instead of Traction Control or something more appropriate makes me think that “off” doesn’t really mean “off” entirely.

Use Case/Background
I’ve had my R1T since March 2022. Nearly 20k miles. Several long trips, lots of towing, exceptionally heavy hauling, and many miles of trails/off road. I’ve been exceptionally pleased with the build, performance, customer service and more. I’ve been in several times for unannounced visits to SC for minor things and they get straightened out quickly. I missed my first scheduled service app’t and it got pushed 3 months to February! Unfortunately this question can’t wait that long.

When driving in muddy conditions, often it is necessary to bypass all traction control/anti-slip. On several occasions, I’ve been in situations where turning “stability” to reduced or off is almost ineffective. Reduced will allow some tire spin but not enough to make much difference. “Off” is really not much better. While it allows more tire spin, it kicks back in after only 1-3 seconds stopping all achieved momentum. The effect of this is frustrating at best. I’ve had to get pulled out of slick conditions on more than one occasion, often by a Wrangler on street tires or something far less capable. With spinning tires, the truck could easily push through or back out of these conditions, but all momentum stops when the traction-control / spin-limiter kicks in - even if set to “off”. The setting doesn’t change, but the effect is as if it did. I have tried Rally, Drift, Deep Sand and other modes but they are all similarly disappointing and ineffective.

I’d like NOT to get into a debate about driving strategies in muddy conditions, so I’m hoping an explanation will not involve driving skills/techniques or reasons why no traction control should not be necessary. Bypassing traction control is indeed required in many situations.
[And while you’re thinking about other mud features, you might want to allow for more “rocking” (back/forth) while in off road mode. The truck prevents effective use of this technique for obvious on-road reasons.]

Do you think a Reset is necessary? Did something get messed up with the (very welcome) Snow Mode OTA? Or is the R1T really designed like this??

Thank you for your attention to this matter. It is important to me for many reasons, and should be to Rivian too for obvious ones.

Anyone else on the Forum experience this behaviour or have workarounds/thoughts?

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[Rexbo]

TL;DR: probably not, but possible with software updates.

So my experience isn't directly applicable but may give insight into the issue: how motor controllers work. This problem has been tricky for electric motorcycle and dirt bike manufacturers for a while, because most motor controllers are split into two categories:
- Current delivery (amps = torque)
- RPM delivery (wheel speed)

For both, the throttle curve is variable but delivery is wildly different.
- Current delivery is proportional to throttle input, regardless of wheel speed, and current is the feedback measure to the controller. This makes electric dirt bikes pretty fun to ride, because once the rear wheel goes from grip to slip, load on the rear tire decreases and the wheel will spin up to match the delivered amperage, but this is fairly easy to modulate with your wrist. However, this would be really bad behavior in a 7000lb truck, so the Rivian uses the other method.
- RPM delivery relies on computers to monitor throttle input and map that to a desired vehicle speed. It then looks at the wheel(s) speed for feedback and determines how much amperage to deliver to the motor. When a wheel spins wildly faster than the measured speed of the vehicle (gps, IMU, wheel speed sensors), generally that's not good news (wheel in the air, on ice, in mud) so the controller cuts current. If vehicle speed inputs go to zero or infinity (all wheels spin freely) the controller feedback loop no longer works.

The problem here is that you cannot fully turn off this feedback loop to the controllers and switch over to current measurement as the feedback device. Dirt bikes (Alta) have tried to spoof how vehicle speed is measured, and widen the wheel speed to vehicle speed delta that's allowed without just runaway power delivery, Rivian has done the same for different drive modes. The problem remains that the inputs can't disagree with each other or you go off the controller mapping.

 

[Arky]

In Rally and Drift "Off" really does seem to mean off. I can feel absolutely no intervention when doing pretty much any maneuver, including an intentional 180 to change direction.

Not sure about general off road modes but I would generally trust Rivian means "off" when they say it.

 

[1550nm]

Thanks for the replies, guys. @Rexbo provides a lot of techincal explanation which is interesting (as far as i can understand it), and @Arky suggests that Rally and Drift will turn traction fully "off" - a claim that doesn't square with my experience. I appreciate both posts.

There are threads on this forum that generate 50+ replies about wheel cap covers and frunk dimensions. I find it surprising that this fundamental feature (design flaw?) has generated such little interest. Quite litterally, the R1T can get stuck in moderate mud when a Ford Taurus would not by virtue of toggled traction control. No word back from my Rivian Guide, so I'm hopping the enlightened on this forum can advise....

 

[RoadTripFan]

Very curious to understand this as well. By no means an expert in any of it but have done some light off roading and been very pleased with the performance. That being said, none of it was slick up to now but that is on my list and would love a better understanding of the system.

 

[Andystroh]

We don’t have much mud here. I did see some interesting behavior in soft sand mode this past summer, where I was climbing a deep sand drift and when the wheels would lose power, they entered this rhythmic series of spurts, where it would give the wheels power, they’d start spinning, then cut it. All while I just had the accelerator depressed. Each one took about 1 second. It was actually pretty effective for climbing up this drift and seemed intentional but I don’t know if that was specific to the soft sand mode.

 

[Riviot]

In my deep snow/slush experience on forest road, I tried giving "gas" with the Drive/Reverse rocker method in different modes and Sand with stability off to no avail. I took a breath, put stability in low, then lightly feathered the gas a few times, then it started to grip, spin, grip, spin, and finally grabbed well enough to take off.

Perhaps we're all used to gunning it and need to learn a new driving habit for off-road with these heavy, smart beasts? Not debating here, just posing a quandary.

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