Brake rotors wearing quesiton

[UnsungZero_OldTimeAdMan]

Are you sure? I thought I read here on site from one of the Geeks that the brakes were applied in regen slowing or just letting up on acclelerator causing the vehicle to come to a stop. If high regen is selected, the brakes were implemented.

No. See above. And see release notes for OTA 2023.50.01.

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[Greg Chick]

I am confident in what I mentioned. The high regen will draw more power from the motors to the battery to increase deceleration. Friction brakes are used in all modes when you reach ~1mph to make a final stop.

So the regen function is not the sole resistance applied to stop the vehicle! What option that is findable on the dash that mimimizes the mechanical brakes?
My intutition tells me slowing way back before the last 50ft. is the key to both tire and brake wear. The new one foot driving skill is a complex skill.

 

[Greg Chick]

No. See above. And see release notes for OTA 2023.50.01.

I will re review the OTA release notes.

 

[beatle]

I don't think we have hard data on D+ using physical brakes. This seems to be one of those rumors that someone mentioned they 'thought' it worked this way and it continuously becomes parroted within an echo chamber to the point where everyone accepts it as true.

Firstly, I use Highway Assist more than most. My brakes still have full pad. I have a 150 mile/day commute (round trip) and my truck has over 36,000 miles. If this was the way they functioned, one would assume I'd be seeing SOME wear at this point.

I sincerely believe the brakes are only recruited *when necessary* based on my anecdotal experience. I get other people share their anecdotes, but in this instance, it's not universal, and I don't believe we have anything in the manual or from Rivian stating it's engineered that way.

I would like to believe that the brake pedal moving during D+ doesn't necessarily indicate use of the friction brakes, but it's what I got. The benefit of D+ far exceeds my desire to maximize range and minimize brake wear. I would love to be wrong here, and instead believe that D+ actually does use regen as much as possible, but the brake pedal movement is certainly suspicious.

I don't think you understand why manual is better than an automatic system. With auto on it can be using brakes where regen would work and you have no say in when the car thinks to apply the brakes vs regen. In manual mode brakes aren't used unless you apply the brake, so 90% you are using regen. In the blended mode my guess is that regen drops to 70% of the time. This will lead to faster pad wear. Also, service confirmed this on my first 7,500 mile service. Service quote, " I would turn the auto blending off if you want to maintain your brakes life, in auto mode it uses the brakes significantly more than with it turned off."

I suppose if you have the ability to let the truck slow down over a great distance you could eek out a bit more regen than if you slow down using brake assist in a shorter, more normal fashion, but otherwise it doesn't matter. Even if you actually drive like this, it's certainly not enough to affect range nor brake pad wear in any meaningful way. Brake assist is only used when the battery is too cold to accept full regen. If the battery is warm enough, you'll get 100% motor regen regardless of brake assist being on or off. If that were not the case, Rivian would force brake assist off after every sleep, just like they kick you out of sport mode - because the truck is EPA tested with it brake assist on, and they want the most regen possible for the highest range estimate.

 

[beatle]

So the regen function is not the sole resistance applied to stop the vehicle! What option that is findable on the dash that mimimizes the mechanical brakes?
My intutition tells me slowing way back before the last 50ft. is the key to both tire and brake wear. The new one foot driving skill is a complex skill.

The option to minimize mechanical brakes is actually under the dash.

 

[shap]

The sad part of this is Rivian transparency in communication - why it is so difficult to provide clarity when friction brakes are used?

My understanding is the brake pedal moves it will engage friction brakes - there is no blending braking in Rivian.

This means that D+ uses friction breaks to control the speed and break when needed. If it also uses regen - probably yes, but it is not clear how much and what the algorithm.

As a separate note, on my original (1st) post question - just stopped at a traffic light near another Rivian (R1S QM), and the right rotor looks very similar to mine. So it is very possible that the way break rotors wear is kind of "in spec".

 

[Greg Chick]

The option to minimize mechanical brakes is actually under the dash.

Where is this brake option under the dash?

 

[beatle]

Where is this brake option under the dash?

Just to the left of the go pedal.

 

[SparkyR1t]

FYI the front calipers are a bolted design ( at least on gen1 trucks they do not slide on pins) but have 6 individual pistons. Racing style Brembo brake system

 

[eddierunner]

I noticed a similar thing early on (2 years ago) and asked Rivian to take a look during a service appointment. They told me the brakes were fine and recommended braking with the pedal several times a week. I haven't been doing this but my brakes are still fine a couple years later.

And for what it's worth, I have had the regen brake assist enabled since the option was added and haven't noticed significant wear to my brakes and according to Recurrent, my vehicle range and efficiency are at the top end of R1Ts on the platform.

 

[shap]

I noticed a similar thing early on (2 years ago) and asked Rivian to take a look during a service appointment. They told me the brakes were fine and recommended braking with the pedal several times a week. I haven't been doing this but my brakes are still fine a couple years later.

And for what it's worth, I have had the regen brake assist enabled since the option was added and haven't noticed significant wear to my brakes and according to Recurrent, my vehicle range and efficiency are at the top end of R1Ts on the platform.

Thank you - great to hear!

I measured mine - they are 10mm (pads). I think they are 11mm when new. So 1mm after 30k is fine.

It is probably fine, just curious why only one rotor is like this

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