R1S Mystery Diagnostic Adventure

[Proxy]

Wheel bearing possibly

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[Glembi2]

Wheel bearing possibly

That’s a good one. Nobody wants to lift the truck solely for rotating the wheels. You could stick your head out the window at speed to listen for whining from the wheels

 

[Proxy]

If I wanted to check the wheel bearings I would jack up each wheel and grab the front and back of the tire and check for play. Then grab the top and bottom and check for play. It would be nice if one could rotate the tire while it is in the air and feel for grinding, but that isn’t going to happen.

 

[riivian]

TL: DR Option 3 below could be the fastest way to figure out what is happening

________

The key point for me is not what happens but when it happens. Those long sweeping curves that gradually trace different length paths has to be it.

You might try these and see what happens:

1. Find a curve that starts the truck shimmying on all purpose. Go back over that section of road again but this time on conserve. That could isolate the issue to be just the rear wheels if the problem does not happen in conserve mode.

2. Try turning on highway assist only after entering the corner. If the truck is fine in the corner but then shimmies on the next straight, my money is on a hardware component making the software think the wheels are turning at different speeds when they are not.

3. The tech should be able to monitor (either via the RIDE menu or via an OBDC monitor) what the wheels are doing when the shimmying starts. Specifically, check how much torque is being applied to each wheel when the truck is shimmying (check the numbers behind the blue bars of each wheel in the settings display). I’m guessing one will be a few percent higher or lower than the rest.

Before TPMS, there was another way to notify drivers that one wheel was underinflated. Count the wheel rotations over a long distance. If one rotated more and all other things being equal, there was a good chance that wheel was under inflated. Rivian could be doing something similar by concluding a wheel was under inflated. But I doubt it.

This a great diagnostic step layout and I have not yet tried the different drive settings as I have been in All Purpose the entire time. I have been logging the Vehicle Diagnostics for the tech (left steering wheel buttons and emergency flasher hold down until it shows up logged) for them each time. This is the first I have done that, so that will give them a date and time stamp with relational data to further assist.

Good tips on this.

 

[riivian]

Wheel bearing possibly

That could be an issue if the wheel when turning experiences some lateral force, it could be sniffing that wheel bearing out past its "good" point and then causing a wobble. But then I wonder why it is not doing it without Cruise or Highway Assist still.

 

[Joe Hoffman]

I’m suspicious of a sensor that’s returning bad values which is causing computer response weirdness.
I would have them replace wheel rotation sensors, and other such related sensors. Also verify the senses are reporting from the correct wheel. For example, did the front right wheel actually get plugged into the front left sensor port confusing the computer during abnormal rotation conditions, such as turning..

 

[Edschwartz1]

Does it happen when lane departure and lane assist are off? Could it have something to do with these sensors?

 

[riivian]

Does it happen when lane departure and lane assist are off? Could it have something to do with these sensors?

I do have those turned off, but in the past with the same issue I did have them turned on. I did however take the advice from the other post and I put it in Conserve mode which I never do. I drove the same stretch of highway and was not able to replicate the vibrating shuddering issue "yet". It was not was full test as I did not go through my normal route and traffic was slow. I have to be over 60mph. But it's was enough for me to think that maybe one of the rear motors "may" be the culprit. I will continue to test later once traffic dies down in the evening.

We could be on to something, maybe......

I have been training an AI Rivian Tech GPT to become and expert on this issue and Rivians in general. But specifically it started as trying to find a solution to this issue. Now with the comment above that I put into it, here is what I got:


----
Understanding that Conserve Mode on your Rivian R1S does not engage the rear motors can be quite revealing in diagnosing the vibration issue. Here’s how this information could help pinpoint the problem:

1. Motor-Specific Vibration: If the vibration disappears when the rear motors are not engaged, it strongly suggests that the issue may be linked directly to one or both of the rear motors or their associated components. This could be due to alignment issues, mounting problems, or even internal motor defects.

2. Drivetrain Dynamics: With only the front motors engaged in Conserve Mode, the drivetrain dynamics change significantly. This shift might alleviate stress or mechanical load on certain components that are otherwise in use when all four motors are engaged, thus eliminating the vibration.

3. Torque and Power Distribution: The difference in torque distribution between the modes could also play a role. In All Purpose mode, the increased torque and power from engaging all four motors might exacerbate an underlying issue that remains dormant when less force is applied through the drivetrain in Conserve Mode.

4. Software and Control Systems: The issue might also be related to the software that controls power distribution and operational parameters for the motors. A software glitch or misconfiguration could cause abnormal behavior only under certain conditions.

Given these insights, it would be advisable to:

• Inform the Service Center: Share these observations with the service center, emphasizing the change in vehicle behavior between driving modes. This detail can guide more targeted diagnostics.

• Check Rear Motors and Components: Inspect the rear motors and their connections, mounts, and any component that is uniquely stressed when these motors are active.

• Software Diagnostics: Ensure that the vehicle’s software is up to date and check for any errors or logs that might indicate issues when all motors are engaged.


This approach should help in further narrowing down the cause of the vibrations and lead to a more effective resolution.
----

I have been training the heck out of this Rivian GPT and correcting it, making it become an expert. Maybe I should post this pubicly for use to all Rivian owners. I hope this is getting close to shuddering issue regardless!!

 

[riivian]

Here is an update on things. I was able to "fully" test this out in the normal stretch of the highway where it does this. I have found that the vibration in the body of the car occurs after I have been on the highway for a 10 minutes or so and I am in Highway Assist or using Cruise Control above 60mph. The vibration does go away after I disengage either, and if I am in Conserve the vibration is about half as intense as when I am in All Purpose.

Either way, it is present in both and only when I am going a fixed speed. As I increase from 60-70 mph it goes away momentarily until I reach 70 or whatever "fixed" speed. At 60 mph in Cruise it's noticeable, at 70mph much worse, and 80+ it's pretty bad.

So as I thinking about this it seems like heat(due to build up time of 10 minutes or so), fixed speed is the issue.

If I had to describe the feeling of this shuddering it would be that of a upper or lower control arm that is worn, or the vibration of an unbalanced wheel without the steering wheel isolation, or even a bent rim. We have rules out the wheels and tires as they have been replaced and are all new and in spec.

With this additional information what do you think it is now?

 

[Glembi2]

Ignoring any software component, that sounds a lot like one rear wheel being harder to rotate than the others. If one wheel was dragging, not receiving enough power to keep it rotating during normal driving at ~70, let’s assume you are manually correcting the steering input to keep the truck centered.

But you would notice the steering wheel rotating when driving straight

That makes me think the torque vectoring system is off - either by a bad wheel bearing or faulty wheel speed sensor.

 

[riivian]

I am feeling you on this and I think the wheel bearing makes sense due to the 10 minute delay that occurs before the issue comes up. Heat is the what exposes this. I think replacing the hubs and bearing may indeed resolve it. We will see next week when it goes in.

 

[Billyt1963]

I am feeling you on this and I think the wheel bearing makes sense due to the 10 minute delay that occurs before the issue comes up. Heat is the what exposes this. I think replacing the hubs and bearing may indeed resolve it. We will see next week when it goes in.

Best of luck in the next leg of this adventure.

 

[riivian]

So, it looks like the ongoing issue with this 2023 R1S Quad may finally be resolved after updating to 2024.19.04!

I took it for a test drive last night on the same stretch of road, and it drove incredibly smoothly. Even though it was nighttime and cooler, I didn't feel any of the previous problems. The ride quality overall has noticeably improved.

I'll continue testing and will report back if the issue reappears, but hopefully, this sixth visit to the service center won't be necessary next week.

If this fix holds, it suggests that the problem might have been related to torque vectoring and was entirely software-based.

Thanks for all the support, everyone. Keep this thread active if you're experiencing similar issues.

I have updated the RiviTech AI public GPT I created on the OpenAi store with these results too. Just search “Rivian” and you will find it.

I hope my issues will help others. Maybe it will never come back if the update is indeed the solution.

 

[riivian]

Tested it all day long in the same stretch of 50 mile highway and the issue is 100% solved. Good job Rivian on doing way more than the software version details cover. Kudos, and I am very happy. Cannot believe how much it change this vehicle. It was driving me nuts, the R1S drives like it's a 2nd gen now!!!

 

[beyondgravity]

i am curious what service notes say for each of these visits?

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