Low speed 'Tocking' when stopping or starting

[M4H4X]

Seems like an expensive band-aid. Hope you're wrong but fear you're right.

Yeah just know it's not a Rivian specific issue -- every EV will have some flavor of this -- just pick any EV -- go to their forums -- search "clunk" or "noise" when decelerating accelerating" or some flavor of that and I guarantee you'll get results.

I'm not convinced that it's an actual safety/longevity problem unless there is excessive play (vibrations, jerkiness) -- but it's real pita of a NVH problem that the industry is going to have to collectively solve.

--

And again not every EV manifests this problem. My Model Y was perfect, my Model S Plaid had the Tesla flavor of this issue plus vibrations.

I don't think the issue is necessarily solvable -- I've had excessive drive lash in previous vehicles (F-150's, F-250's, Rams, etc...) and you could feel it but not hear it because of the ICE.

I think the CV half-shaft assembly needs to be eliminated all-together. It's a point of inefficiency and a point of failure that could be eliminated by a motor-hub-assembly. If Lucid can make a motor assembly that can fit in a piece of standard luggage -- eventually we will be able to get sufficient power/longevity out of a pancake design as well.

(Note: The only unsprung weight in this type of assembly would be the wheel/tire/brake disk/rotor shaft/windings or magnet (which ever is moving))

A lot of practical issues to solve for those as well due to the impacts/vibrations they would have to cope with:

https://evcentral.com.au/why-dont-evs-have-four-in-wheel-motors/

If we can make a wheel bearing last 160,000 miles though; I'm confident we can make an electric motor subjected to that stress do the same.

This vaporware company was on that path (are they dead lol?)

https://www.lordstownmotors.com/pages/endurance

Edit: lol -> https://cleantechnica.com/2022/10/03/lordstown-motors-somehow-not-dead-builds-2-trucks/

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[Yellow Buddy]

Yeah just know it's not a Rivian specific issue -- every EV will have some flavor of this -- just pick any EV -- go to their forums -- search "clunk" or "noise" when decelerating accelerating" or some flavor of that and I guarantee you'll get results.

I'm not convinced that it's an actual safety/longevity problem unless there is excessive play (vibrations, jerkiness) -- but it's real pita of a NVH problem that the industry is going to have to collectively solve.

--

And again not every EV manifests this problem. My Model Y was perfect, my Model S Plaid had the Tesla flavor of this issue plus vibrations.

I don't think the issue is necessarily solvable -- I've had excessive drive lash in previous vehicles (F-150's, F-250's, Rams, etc...) and you could feel it but not hear it because of the ICE.

I think the CV half-shaft assembly needs to be eliminated all-together. It's a point of inefficiency and a point of failure that could be eliminated by a motor-hub-assembly. If Lucid can make a motor assembly that can fit in a piece of standard luggage -- eventually we will be able to get sufficient power/longevity out of a pancake design as well.

(Note: The only unsprung weight in this type of assembly would be the wheel/tire/brake disk/rotor shaft/windings or magnet (which ever is moving))

A lot of practical issues to solve for those as well due to the impacts/vibrations they would have to cope with:

https://evcentral.com.au/why-dont-evs-have-four-in-wheel-motors/

If we can make a wheel bearing last 160,000 miles though; I'm confident we can make an electric motor subjected to that stress do the same.

This vaporware company was on that path (are they dead lol?)

https://www.lordstownmotors.com/pages/endurance

Edit: lol -> https://cleantechnica.com/2022/10/03/lordstown-motors-somehow-not-dead-builds-2-trucks/

There's different clicks, clunks, whirrs, blips, and bops though.

On the Ford F-150L which you posted before, the click is actually the intended action of the brakes. At low speed, they blend in the physical brakes and utilize that for hold. As a result, instead of the smooth feeling you get like in a Tesla or the Rivian, you get a shift in weight and a sound - very similar to how a transmission feels and sounds when shifting gears.

On my R1T, the click...wasn't there when I got the vehicle. It didn't develop until about 2000 miles which is a bit of a concern. It's one thing if it was intended, but developing a click - from a manufacture that seems to have issues with proper torque/tightening on other components...certainly a concern until proven otherwise.

 

[M4H4X]

On the Ford F-150L which you posted before, the click is actually the intended action of the brakes. At low speed, they blend in the physical brakes and utilize that for hold. As a result, instead of the smooth feeling you get like in a Tesla or the Rivian, you get a shift in weight and a sound - very similar to how a transmission feels and sounds when shifting gears.

Our trucks do this too -- it's the only way to generate sufficient stopping torque at low speeds. And consequently it's also one scenario that can cause the tock -- as the torque on the halfshaft assembly shifts from a braking torque provided by the motor to a braking torque applied by the brakes the lash in the drivetrain will present itself (which is natural on any drivetrain, if things were too tight it would cause excessive wear) because the force shifted from one side of the drivetrain to the other. Which if there is any noise generated by that change in slack that's when you would hear it in addition to when quickly accelerating/braking.

On my R1T, the click...wasn't there when I got the vehicle. It didn't develop until about 2000 miles which is a bit of a concern. It's one thing if it was intended, but developing a click - from a manufacture that seems to have issues with proper torque/tightening on other components...certainly a concern until proven otherwise.

On this point we are in complete agreement. Regardless of the symptom, source, it is a concern that needs a solution.

 

[Yellow Buddy]

My plaid had this issue but my Y didn’t. My R1T (250miles on it.) has also already started “tocking”. It seems minor though.

Anyways, the procedure to fix the problem is the EXACT SAME over in Tesla land.

1) Grease the hub/splines and retorque. Comes back after a few hundred to a thousand miles or so.

2) Once extreme enough Tesla replaces the shafts. (Still noise eventually returns.)

And the cherry on top is I see the same talk about some hypothetical “redesigned shafts” that never materialize. (I’ve been off that train for a few months … so Tesla might have something by now, might not?)

I’m sure that @jebinc has dealt with this.

Did you get the same story I did?

I got several shafts replaced and was told the reason for it was due to "excessive power". The officially recommended solution was to leave the suspension in Low, and to avoid hard acceleration.

A little dated but...

Tesla: For $2,500 you can upgrade to a nifty adjustable suspension . Want it?
Tesla: For $20,000 we can also make your car go REALLY fast. Want it?

Tesla: Btw, to make sure your $100k vehicle doesn't break, just make sure you don't use either of those ok?

Tesla: What? It broke? No, it's normal sounds. What was that? You're past warranty? Oh, it needs new shafts. That'll be $5,000 please.

 

[Yellow Buddy]

Our trucks do this too -- it's the only way to generate sufficient stopping torque at low speeds. And consequently it's also one scenario that can cause the tock -- as the torque on the halfshaft assembly shifts from a braking torque provided by the motor to a braking torque applied by the brakes the lash in the drivetrain will present itself (which is natural on any drivetrain, if things were too tight it would cause excessive wear) because the force shifted from one side of the drivetrain to the other. Which if there is any noise generated by that change in slack that's when you would hear it in addition to when quickly accelerating/braking.

I don't think ours is intentional though. I think our blend is smooth and - just from perception - activates at a significantly lower speed.

The F-150L is very very deliberate and activates at a much higher speed. I haven't seen anyone come out and say it, but I think it's deliberate to give ICE to EV transition drivers comfort. It'll clunk both on acceleration and deceleration as the brake stays engaged for a little while and you can feel it let go when accelerating.

I haven't seen that on the Rivian, only very low speed grabbing for stopping.

 

[M4H4X]

I don't think ours is intentional though. I think our blend is smooth and - just from perception - activates at a significantly lower speed.

The F-150L is very very deliberate and activates at a much higher speed. I haven't seen anyone come out and say it, but I think it's deliberate to give ICE to EV transition drivers comfort. It'll clunk both on acceleration and deceleration as the brake stays engaged for a little while and you can feel it let go when accelerating.

I haven't seen that on the Rivian, only very low speed grabbing for stopping.

No I agree it is smooth. What i'm trying to say here is -- no matter if it is smooth or not -- the moment the torque from the brakes exceeds the torque provided by regen (and that moment will exist no matter if it's a smooth or unsmooth transition) the play in the driveline lash will reverse.

Fellow tockers go out and decelerate at a moderate pace and I guarantee you will be tockin' along at roughly 15-20mph as the braking strength exceeds the regen strength. And you will tick-tock the clock with a soft or hard pedal press as you accelerate (and the amplitude of the rockin' tock will be relative to the force applied to the accelerator.)

 

[s4wrxttcs]

Anyone have clicking like this and get it resolved yet? I guess it’s more like a squeak

That's the same sound mine is making, and I believe this entire thread is about that sound or similar sound.

There does seem to be variations of it.

Post #19 has almost exactly the same sound as yours.

 

[AdamUCF]

Picking it up later. Hopefully it's fixed ?

Well it wasn't fixed. I'm not sure what the point of replacing the halfshaft and hub bearings was because it sounds the same. I assume they noticed something was wrong with them but seems strange. I spoke with the tech and he said all the trucks make the sound and it's considered normal. It really doesn't bother me but the whole situation is strange to me. Like is it a problem or is it not?

What is annoying me and they claimed they fixed but didn't was a rattle coming from my drivers door. Seems related to the flashlight but removing it doesn't fix it.

 

[Zoidz]

...

I think the CV half-shaft assembly needs to be eliminated all-together. It's a point of inefficiency and a point of failure that could be eliminated by a motor-hub-assembly. If Lucid can make a motor assembly that can fit in a piece of standard luggage -- eventually we will be able to get sufficient power/longevity out of a pancake design as well.


(Note: The only unsprung weight in this type of assembly would be the wheel/tire/brake disk/rotor shaft/windings or magnet (which ever is moving))

The additional unsprung mass is not insiginificant. Lordstown adds about 70 lbs of unsprung weight per wheel with their hub motor design - that's roughly doubling the unsprung weight. That requires stronger suspension components and will have a negative impact on ride.

 

[M4H4X]

The additional unsprung mass is not insiginificant. Lordstown adds about 70 lbs of unsprung weight per wheel with their hub motor design - that's roughly doubling the unsprung weight. That requires stronger suspension components and will have a negative impact on ride.

That is very true, it’s essentially doubling the weight.

Perhaps with the use of some special materials and maybe even integrating the rotor into the wheel itself (i.e. the barrel of the wheel IS the rotor.) That weight can come down.

You can’t reduce the mass of the rotor, but you CAN reduce the mass of everything else around it.

 

[yizzung]

Thought it was worth mentioning in this thread that my tock is gone. I had my mobile recall service on Friday, which took 10 minutes, and drove all weekend tock-free. I haven't seen many reports of disappearing tocks following the recall torque tune, but I don't have it anymore.

My tock could be reliably produced when accelerating from a dead stop and when decelerating at low speeds. Will be interesting to see if it eventually returns after I log more miles, but for those out there experiencing the tock, at least in this one instance, it seems to have been fixed without replacing (or greasing) a bunch of different parts in the front end of the truck. YMMV.

 

[DaveA]

Thought it was worth mentioning in this thread that my tock is gone. I had my mobile recall service on Friday, which took 10 minutes, and drove all weekend tock-free. I haven't seen many reports of disappearing tocks following the recall torque tune, but I don't have it anymore.

My tock could be reliably produced when accelerating from a dead stop and when decelerating at low speeds. Will be interesting to see if it eventually returns after I log more miles, but for those out there experiencing the tock, at least in this one instance, it seems to have been fixed without replacing (or greasing) a bunch of different parts in the front end of the truck. YMMV.

Nice to hear (or not hear, tock wise?) The recall fixed my slight pull to the right...so that was also a nice surprise.

 

[Mandarin]

Seems like this issue is getting to another level (saying hello to all former and current Model X owners).

Last week I had an appointment for lubricating that squeaking noise all trucks are doing, they fixed it. I brought up this tocking/clunking/knocking noise to their attention. Even one tech was out and took a ride with me and was able to confirm the sound.

After service, they told me it is LH CV-shaft related (of course I knew it) and told me to watch if it will be getting worse.

A week later it got cold here (40-50F) and I noticed 2 things:

1. Vibrations under hard acceleration (all propose mode) - As I said - hello Model X owners ))
2. That tocking/clunking/knocking noise is more noticeable now. Especially after overnight parking. However, after 25-30 miles of driving it goes down to the same noise level as it's being a week ago.

I think this is not spline related issue as shown on the video for model 3 a page or 2 ago. I used to live in a really cold climate and had an 08" Subaru Legacy, when it was from -10F to -25F outside the lubrication inside the CV shafts was getting frozen and there was the same noise... We were fixing it by adding or replacing lubrication inside front CV axels... Just my 5c here

That noise is getting me crazy every time I hear it. Especially after Mode X with those issues, after S Plaid with those vibrations...

 

[NooterIA]

I had the recall fix and my tock remains.. hearing at least three or four songs n every acceleration from stop and the same on stopping. It’s the same in sport, conserve and all purpose. Annoying!

 

[NY_Rob]

Seems like this issue is getting to another level..

Ride it hard and let it blow out... seems like the only way to shine some light on this issue.

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