Stiff front suspension under acceleration

[cadamo001]

Cyberbeast here. I've noticed something and wondering what the rest of the owners have noticed. Under normal conditions, bumps are absorbed and the suspension is great. When accelerating however, it seems like the front suspension gets SOOOO stiff that it's super jarring over small to mid sized bumps. Like there is not suspension in the front at all. I'm not launching, just accelerating. And not WOT, just normal accelerating. It's like it's a bug in the software for the active dampening but wanted to see if anyone else here has noticed this or is this just a ticket I need to open?

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[cyberag]

I have the same problem with my cyberbeast. Have you found any resolution?

 

[HaulingAss]

Cyberbeast here. I've noticed something and wondering what the rest of the owners have noticed. Under normal conditions, bumps are absorbed and the suspension is great. When accelerating however, it seems like the front suspension gets SOOOO stiff that it's super jarring over small to mid sized bumps. Like there is not suspension in the front at all. I'm not launching, just accelerating. And not WOT, just normal accelerating. It's like it's a bug in the software for the active dampening but wanted to see if anyone else here has noticed this or is this just a ticket I need to open?

It sounds like the massive combined torque from the two rear motors is extending the front suspension all the way, for the same reasons fast dragsters need wheelie bars. The Beast can't accelerate fast enough to actually lift the front wheels (without help from a bump in the pavement) but it can cause the front suspension to ride nearly fully extended.

In suspension terminology, this is called "topping out" and can cause a jittery and harsh feeling as the suspension rides near or hits its upper stops. This can be reduced, but maybe not eliminated, by avoiding "Comfort" suspension mode and using the lowest ride height setting. The firmer setting dials in more suspension damping which reduces bouncing and a lower ride height gives you more suspension travel to work with.

Also, make sure you have the full 50 psi cold in the tires, an underinflated tire can exacerbate the motion by being bouncier when the suspension is lightly loaded (as it is under full acceleration).

Most pickup owners would give their left nut to have this "problem".

 

[Art138]

Vin 27xxxx, I have not noticed the aforementioned anomoly but then our roads are pretty good down here. To the contrary the front tilts up somewhat during Beast mode run ups.

 

[cadamo001]

It sounds like the massive combined torque from the two rear motors is extending the front suspension all the way, for the same reasons fast dragsters need wheelie bars. The Beast can't accelerate fast enough to actually lift the front wheels (without help from a bump in the pavement) but it can cause the front suspension to ride nearly fully extended.

In suspension terminology, this is called "topping out" and can cause a jittery and harsh feeling as the suspension rides near or hits its upper stops. This can be reduced, but maybe not eliminated, by avoiding "Comfort" suspension mode and using the lowest ride height setting. The firmer setting dials in more suspension damping which reduces bouncing and a lower ride height gives you more suspension travel to work with.

Also, make sure you have the full 50 psi cold in the tires, an underinflated tire can exacerbate the motion by being bouncier when the suspension is lightly loaded (as it is under full acceleration).

Most pickup owners would give their left nut to have this "problem".

I've noticed this under custom with beast acceleration, High Ride Height. It also seems to happen under ANY acceleration, not just WOT. Like the active dampening engages under any acceleration and stops the front suspension from working at all.

There is a road right outside my development that has a bump large enough to make a large jarring impact where I can test. I'll try different suspension heights but I'm doubtful...

Please standby...

 

[SentinelOne]

Out of spec noticed this on the beast model (but not AWD) quite a while ago. I notice this too on my CB, it's any acceleration not just WOT....if coasting it's Cush, if under any throttle it's a bit harsh. I wouldnt say "no suspension" stiff for me, but definitely noticeable / different. Im aware of it and let off the throttle if I see something that would cause it to be harsh....

hopefully something they can tune out w/ SW update if they're even aware of it...but maybe not. Weird thing is both CT and CB both only have single motor in the front so you wouldnt think diff behavior (at least if not at WOT with 2 beast motors trying to wheelie)

 

[cyberag]

It’s there for me also when decelerating. I have been using high comfort so I’ll have to try some of the other settings. I don’t think this just occurs when at the limits of the suspension travel. Seems to be when the driveshafts are engaged the suspension travel becomes limited. I’m always looking for potholes so I can make sure I coast over them otherwise it’s going to rattle the teeth. It can be pretty alarming to passengers.

 

[cadamo001]

Out of spec noticed this on the beast model (but not AWD) quite a while ago. I notice this too on my CB, it's any acceleration not just WOT....if coasting it's Cush, if under any throttle it's a bit harsh. I wouldnt say "no suspension" stiff for me, but definitely noticeable / different. Im aware of it and let off the throttle if I see something that would cause it to be harsh....

hopefully something they can tune out w/ SW update if they're even aware of it...but maybe not. Weird thing is both CT and CB both only have single motor in the front so you wouldnt think diff behavior (at least if not at WOT with 2 beast motors trying to wheelie)

I actually sent Kyle a note on this on the Rivian formums I’m on with him. He never responded. I didn’t know that he posted his thoughts on this. At least I know it’s not just my truck. I don’t have any issue at all when I’m coasting. I have the exact same symptoms as you sentinel one.

 

[mrmeta]

I wanted to see if anyone had any updates on this? (I have the exact same issues with my Cyberbeast.)

 

[cadamo001]

Not for me. I am hoping with every update it disappears, but it hasn't...

 

[Crissa]

Isn't stiff suspension better for control under acceleration? The tires need to be pushed hard back against the ground so they remain in contact?

Isn't that why sports cars have stiff suspension?

-Crissa

 

[cadamo001]

Stiff yes. But it's ROCK HARD under acceleration. Just the front. Like you are hitting a curb with even the smallest bump. It has to be something with the dynamic roll control or suspension or whatever in the front. It's not tuned correctly. I just haven't gotten around to opening a ticket since it doesn't bother me that much. But it's not right.

 

[cadamo001]

This was again confirmed with OOSs latest YT video. It’s exactly the same symptom I have on my beast.
Kyle also mentioned a recall for all beasts that I wasn’t aware of. I just asked my service center about it. Waiting to hear back.

 

[Jason B]

This was again confirmed with OOSs latest YT video. It’s exactly the same symptom I have on my beast.
Kyle also mentioned a recall for all beasts that I wasn’t aware of. I just asked my service center about it. Waiting to hear back.

I bet they say it’s normal

 

[Dazureus]

I think this has been discussed before and it has to do with the motor configuration difference between the AWD and Cyberbeast. The AWD uses a permanent motor in the rear and induction motor on the front. The Cyberbeast uses the permanent motor on the front and two induction motors in the back. Permanent motors are more efficient at lower RPMs since you don't need additional electricity to charge the induction coils to overcome inertial moment.

If the information is correct, the AWD rear biases power upon dead stop acceleration and the Cyberbeast front biases power in the same circumstances. That high torque at low RPM over bumps can cause the harsh noise that sounds like suspension slamming. You can test this by going into baja mode and biasing the power to the rear or using slip start to see if the harsh feel is still present.

I've definitely felt the same thing in my CB on washboard dirt roads around me. I think some kind of always on slip start, or a redistribution of power at low speeds would be required to fix this, but it would probably include a small hit to battery efficiency.

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