Unsettling brake behavior

[ThirteenElectrics]

Twice on a recent road trip I needed to rapidly decelerate from 60+ MPH on a dry road. Regen was set to high. Upon pressing the brake pedal, the brakes felt "dead"--like I didn't have any hydraulic assist. Upon taking my foot off and re-applying, the brakes then seemed to "work".

I think this might be a side effect of brake blending, where strong regen automatically depresses the brake pedal, but it was unsettling; it felt like the brakes weren't working, because there was a hard-ish stop in the pedal. In other words, there was very little give, like I was hitting a wall.

Has anyone else experienced this?

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[POLAR1S]

Yea something like that. Honestly, I don't like the brake pedal feel.
Travel is long too if you need to stop.. travel is too long for the gas pedal too.

 

[Singletracker]

I have not experienced that exact phenomenon. However, I have recently disabled the blended braking feature and this is why.

While cruisng down out the mountains, on relatively flowing road, I noticed on the driver‘s display, that every time I eased off the throttle for a corner, even a little, the brakes lights were coming on. My first thought was, this is ridiculous. NO, I’m not frickin’ braking, just slowing. That must be driving the drivers behind me nuts. I hate driving in the mountains behind people who are constantly on and off the brakes, for no apparent reason. Every corner seems to be a surprise to them. I always wonder how often they have to do a brake job. I can go forever on a set of pads.

Then I realized, that with the blended braking feature engaged, the truck was using the brakes constantly, rather than relying on regen, with a little manual assist. I pulled over and disengaged the blended braking. After that, I was able to get a nice flow down the mountain without the brake lights constantly cycling on and off. Yes, the regen was reduced because of the longish decline and I did have to manually use the brakes occasionally. But, that was no biggie. About this time it became clear to me that, although the brake blending feature works very well and does offer a very smooth ride, it surely must dramatically increase brake pad wear. For now, I’ll be leaving it off.

 

[jfoonly]

I hate driving in the mountains behind people who are constantly on and off the brakes, for no apparent reason. Every corner seems to be a surprise to them.

Ha! I feel the same. In my ICE pickup, I'd just cruise in 3rd gear, modulating gas a bit as needed. I love the regen downhill, but it does shine the brake lights too, even without blended braking enabled. Maybe not quite as much though?

 

[Singletracker]

Ha! I feel the same. In my ICE pickup, I'd just cruise in 3rd gear, modulating gas a bit as needed. I love the regen downhill, but it does shine the brake lights too, even without blended braking enabled. Maybe not quite as much though?

Exactly. That why they have a transmission. Even with an automatic trans, I would regularly use the gears in the mountains, even for around town. It makes for a much smoother ride. I’m definitely not a slow driver, but I do value smooth. Quick and smooth

The brakes lights frequency is definitely much more subdued with the blending feature off. It’s down to a reasonable level. Not sure exactly what determines when the brake lights are activated. Certainly, if the brakes are activated, the lights are going on. But, the main thing for me was the realization of how often the truck was using the brakes. I had no idea. This could get expensive.

 

[s4wrxttcs]

I have blended brakes turned off and I've never experienced this.

I do anticipate reduced braking action if I haven't used the brakes in a while. So I might be subconsciously doing a double tap.

 

[Singletracker]

Is there not a limited amount of blending occurring even when the blending feature is off - as in the last few feet, yards or whatever before coming to a complete stop?

To the OP’s experience, I will say, I also run high regen and, on those occasions when I have to stop extra quickly, I have found the brake pedal to be pretty mushy. It gets the job done, but……

 

[iamnid]

How does one turn the brake blending off? I don't recall seeing this in the options.

 

[CrazyOne]

How does one turn the brake blending off? I don't recall seeing this in the options.

I don't think it's really blended braking as in a hybrid Toyota. This is Regen assist when Regen is limited because of battery state( too high charge, too cold, too hot , etc)

I have the Regen assist off as you never know how long the vehicle has been riding the brakes and if they are overheated to the point of failure. I prefer to know when my car uses the friction brakes.

Brake pedal is friction brakes only.

 

[Ecupip]

Ha! I feel the same. In my ICE pickup, I'd just cruise in 3rd gear, modulating gas a bit as needed. I love the regen downhill, but it does shine the brake lights too, even without blended braking enabled. Maybe not quite as much though?

Most modern cars (small displacement and turbocharged) have little engine braking. No matter what gear you drop down to, you won't get much assistance down a mountain. That's why we see brake lights more these days.

 

[Bullwinkle]

I have not experienced that exact phenomenon. However, I have recently disabled the blended braking feature and this is why.

While cruisng down out the mountains, on relatively flowing road, I noticed on the driver‘s display, that every time I eased off the throttle for a corner, even a little, the brakes lights were coming on. My first thought was, this is ridiculous. NO, I’m not frickin’ braking, just slowing. That must be driving the drivers behind me nuts. I hate driving in the mountains behind people who are constantly on and off the brakes, for no apparent reason. Every corner seems to be a surprise to them. I always wonder how often they have to do a brake job. I can go forever on a set of pads.

Then I realized, that with the blended braking feature engaged, the truck was using the brakes constantly, rather than relying on regen, with a little manual assist. I pulled over and disengaged the blended braking. After that, I was able to get a nice flow down the mountain without the brake lights constantly cycling on and off. Yes, the regen was reduced because of the longish decline and I did have to manually use the brakes occasionally. But, that was no biggie. About this time it became clear to me that, although the brake blending feature works very well and does offer a very smooth ride, it surely must dramatically increase brake pad wear. For now, I’ll be leaving it off.

Disengaging brake blending should increase regen.

 

[SparkyR1t]

I have not experienced that exact phenomenon. However, I have recently disabled the blended braking feature and this is why.

While cruisng down out the mountains, on relatively flowing road, I noticed on the driver‘s display, that every time I eased off the throttle for a corner, even a little, the brakes lights were coming on. My first thought was, this is ridiculous. NO, I’m not frickin’ braking, just slowing. That must be driving the drivers behind me nuts. I hate driving in the mountains behind people who are constantly on and off the brakes, for no apparent reason. Every corner seems to be a surprise to them. I always wonder how often they have to do a brake job. I can go forever on a set of pads.

Then I realized, that with the blended braking feature engaged, the truck was using the brakes constantly, rather than relying on regen, with a little manual assist. I pulled over and disengaged the blended braking. After that, I was able to get a nice flow down the mountain without the brake lights constantly cycling on and off. Yes, the regen was reduced because of the longish decline and I did have to manually use the brakes occasionally. But, that was no biggie. About this time it became clear to me that, although the brake blending feature works very well and does offer a very smooth ride, it surely must dramatically increase brake pad wear. For now, I’ll be leaving it off.

Like many EV’s that utilize regen the brake lights illuminate each time you release the throttle regardless if standard braking is involved. Some EV’s are more intelligent than others and take rate of deceleration into account before illuminating the brake lights

 

[riv-e-in]

How does one turn the brake blending off? I don't recall seeing this in the options.

https://www.rivianforums.com/forum/threads/lotta-brake-dust-r1s-quad.32359/page-2#post-607705

 

[ThirteenElectrics]

I don’t turn blended braking off because I want my brakes to be consistent regardless of state of charge or conditions. This mushy pedal is a glaring inconsistency, though.

 

[Singletracker]

Like many EV’s that utilize regen the brake lights illuminate each time you release the throttle regardless if standard braking is involved. Some EV’s are more intelligent than others and take rate of deceleration into account before illuminating the brake lights

When coming down the mountain the other day, I definitely noticed very significant reduction in brake light activation after I disabled the brake blending feature. Looking back, some of that may have been because the car had already reduced the regen to a minimum based on battery conditions. No brakes. No regen. No brake lights. I’ll be testing this further and hope that there is a rate of deceleration element factored into this light activation.

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