Brake pad wear?

[Goose]

I only have 3200 miles on my S, exclusively in High Regen, so not the best comparison, but after my drives, (including the top of Loveland Pass in the Rockies and back down) the front calipers are cold, and from the photos, I don’t think my rear pads have ever touched the rotors, as witnessed from the brand new striations still present on the rear rotors…would be interesting to see others’ rotor photos.

Great to know! That kind of shoots down my theory but that's not a bad thing.

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[hayduke]

Another data point: my truck has about ~12k miles, probably 80-90% of time in high regen all purpose mode. 20" AT tires. The other 10-20% is off road or snow mode where I think regen is lower.

Rotors don't have visible dust, and wear looks similar to @opnwide 's ... didn't measure but I'd guess close to ~10 mm or more. not sure how fat the pads were to start with.

so, this doesn't seem to affect everyone.

i also figured that i would not need to worry about pad or rotor wear for many years of ownership. hope this ends up being a fixable problem with a known root cause.

 

[68wske]

I don’t think I saw this mentioned, but these trucks do use the hydraulic brakes to at least assist in adjusting speed with cruise/driver+. Not saying that explains it, but..

 

[R1Tom]

I am again surprised by this....this vehicle is not really novel in many EV ways. Like brakes. Nothing special....like all other EV's with regen braking. And others blazed the way and went thru the learning curve. So I assumed, maybe wrongly, that things like the braking system, would have benefitted from other EV manufacturers already pushing the learning curve, and we wouldn't be seeing things like severe premature brake wear in some instances, with the Rivians.

 

[zefram47]

I don’t think I saw this mentioned, but these trucks do use the hydraulic brakes to at least assist in adjusting speed with cruise/driver+. Not saying that explains it, but..

Gonna have to counter this. On cruise you can clearly watch the gauge next to the speedometer show regen use while slowing down. I've yet to see it adjust speed enough that the brake lights even come on, so there'd be no reason for the friction brakes to come into play.

 

[68wske]

Gonna have to counter this. On cruise you can clearly watch the gauge next to the speedometer show regen use while slowing down. I've yet to see it adjust speed enough that the brake lights even come on, so there'd be no reason for the friction brakes to come into play.

I won’t argue with those facts, but does your brake pedal not physically move like mine does?

 

[Yossarian]

. . .
so, this doesn't seem to affect everyone.

i also figured that i would not need to worry about pad or rotor wear for many years of ownership. hope this ends up being a fixable problem with a known root cause.

Amen brother, amen.

 

[Dark-Fx]

Just had a chat with the technician here in Chelsea, MA. They have seen three examples of this in New England and have elevated this for further inquiry. The working theory is that the climate in New England (wet and cold) creates rust on the pads. (I think this is a known EV issue friends in Norway had to change rotors because they were rusted ). The difference with Tesla is the hold feature that actually holds the Rivian whereas Teslas will "creep". That is the story and it makes sense. My technician said Rivian is looking into what this will mean for warranty etc. As mentioned early they took the labor off immediately. Should have my truck back in an hour or two.

A little friendly comparison, this is what the front rotor/pads look like on my Polestar 2 after two winters and only 13,500 miles. Polestar fully blends the brake pedal, so unless you're braking hard regularly, they essentially go unused. Rivian doesn't blend so they should still get occasional use and will look better longer, but it probably results in more wear. Not "worn out after 30k miles" wear though, something else has to be going on there.

Polestar also does a brake hold at stops.

 

[Sgt Beavis]

Just had a chat with the technician here in Chelsea, MA. They have seen three examples of this in New England and have elevated this for further inquiry. The working theory is that the climate in New England (wet and cold) creates rust on the pads. (I think this is a known EV issue friends in Norway had to change rotors because they were rusted ). The difference with Tesla is the hold feature that actually holds the Rivian whereas Teslas will "creep". That is the story and it makes sense. My technician said Rivian is looking into what this will mean for warranty etc. As mentioned early they took the labor off immediately. Should have my truck back in an hour or two.

Boy that response sounds fishy. I guess I’ll check my brakes today. I’m at 16000 miles and do a lot of my driving in the mountains. I barely use my brakes. Especially when compared to braking on my Jeep.

 

[av8or]

I won’t argue with those facts, but does your brake pedal not physically move like mine does?

This right here! The brake pedal moves up and down a lot when slowing and stopping in my truck. I was surprised to see it and don’t understand why it’s necessary.

 

[kurtlikevonnegut]

I don’t think I saw this mentioned, but these trucks do use the hydraulic brakes to at least assist in adjusting speed with cruise/driver+. Not saying that explains it, but..

I was told this by a service tech as well (albeit not a Christmas party so TFWIW). I think the primary reason for this is ACC is reactive by nature as opposed to proactive, so any time the speed has to be adjusted due to other vehicles, it is more likely to apply hydraulic brakes than a driver who is anticipating traffic around them. As @Dark-Fx said, this still wouldn't explain needing replacement at 30,000 miles, but it would mean more brake involvement than you might expect if you use it frequently.

 

[shap]

I was told this by a service tech as well (albeit not a Christmas party so TFWIW). I think the primary reason for this is ACC is reactive by nature as opposed to proactive, so any time the speed has to be adjusted due to other vehicles, it is more likely to apply hydraulic brakes than a driver who is anticipating traffic around them. As @Dark-Fx said, this still wouldn't explain needing replacement at 30,000 miles, but it would mean more brake involvement than you might expect if you use it frequently.

I just checked my X5 - when on AutoPilot (Line centering + adaptive cruise), when it needs to slow down it does use regenerative breaking, basically simulating a driver pushing a bit on the brakes pedal. It will start using friction brakes if stronger breaks needed to be applied. I am not sure why would Rivian do it differently.

P.S. The only difference - I think all pedals in X5 are electronic.

 

[kurtlikevonnegut]

I just checked my X5 - when on AutoPilot (Line centering + adaptive cruise), when it needs to slow down it does use regenerative breaking, basically simulating a driver pushing a bit on the brakes pedal. It will start using friction brakes if stronger breaks needed to be applied. I am not sure why would Rivian do it differently.

P.S. The only difference - I think all pedals in X5 are electronic.

I don't mean to say that the Rivian doesn't also use regen when ACC is on, just that it is more likely to use hydraulic brakes in addition to regen than a person who is controlling the throttle is. Basically, it will be much more quick to apply hydraulic brakes and a driver may not realize that they are being used.

 

[av8or]

I don't mean to say that the Rivian doesn't also use regen when ACC is on, just that it is more likely to use hydraulic brakes in addition to regen than a person who is controlling the throttle is. Basically, it will be much more quick to apply hydraulic brakes and a driver may not realize that they are being used.

It is interesting that even slight slowing shows regen, but also the peddle moves slightly. I’ve been using adaptive cruise in stop and go traffic, and the way it runs up on other cars and slams on the brakes (the peddle goes down pretty hard) it could use up some brake pad. I wonder if the OP uses adaptive/driver+ a lot…..

 

[shap]

"peddle moves slightly" is normal - it should mimic the driver slowing down (aka push on the peddle).

Let's assume there is no one pedal driving (no regeneration at all by lifting the gas peddle). When the Driver will push on the brake pedal, it will start regeneration to slow down the car, and then blend with the friction brakes if needed. With AutoPilot - X5 will slow down (and peddle will move slightly as well). And if needed it will blend with friction brakes and push peddle even further.
That is all normal.

I guess what we are talking about here is, why Rivian, which is able to slow down very significantly only by using regen, may use friction brakes at all.

The only explanation I found is, REGEN will not work when the invertor is overheated - and in this case only friction brakes will be used. I do not see how this can happen in regular driving, but if you go down the mountains, you can get this problem pretty easily. This is one of the very known Rivian issues, along with battery thermal management.

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