Sponsored

Steep Declines - avoiding friction brakes

Hawaii Guy

Member
Joined
Mar 9, 2023
Threads
1
Messages
7
Reaction score
0
Location
Hawaii
Vehicles
NA
Awaiting my (repeatedly delayed) delivery to HI….Wondering if anyone out there can share their experience with steep declines and crawl speeds. Basically, the access road I use everyday is a 1.4 mile poorly paved/rutted out 4WD-only road with an average incline of 25 degrees and a max incline of 45 degrees. Because I immediately pass through several 2-3 ft deep waterways after my decline, it’s critical that I don’t use friction brakes on my descent…lest I warp those hot brakes upon cooling in the water. Currently my 2014 Taco handles the work just fine in 4LO. Rivian has replied with cautiously optimistic enthusiasm in emails saying the decline holding capacity is actually inferior compared to Magna Steyr 4LO systems. But I certainly cannot afford to have a $75k hunk of metal delivered to me only to end up useless on my daily commutes into and out of the valley below. Looking for anyone who’s dropped their R1T down anything remotely similar to my steep situation. Thanks in advance.
Sponsored

 

rivian_germany

Well-Known Member
First Name
D-Rok
Joined
Dec 28, 2022
Threads
4
Messages
122
Reaction score
243
Location
Germany
Vehicles
'22 R1T, '22 M3LR, '09 Honda Odyssey
Occupation
Software Engineer
Clubs
 
If you are at a high charge level (85+%), it won't regen very well, but in my experience the regen under that is typically amazing. Like, "brake-check" amazing. As long as you don't build up lots of speed, it will regen like mad, no way you'll use brakes. The only time I have to use my brakes is on the Autobahn, after going 100+mph, and trying to stop quickly and merge onto a ramp, it will lose some regen capacity from about 75-45mph. But downhill at a slow speed it should easily keep up the regen! I suspect but have not tried, that it would hold still even on a 45 decline due to regen and you will be forced to use the accelerator most of the way down. You should test drive one if possible... and be amazed..
 

shrink

Well-Known Member
Joined
Feb 16, 2021
Threads
67
Messages
1,050
Reaction score
1,868
Location
Phoenix, AZ and Kailua-Kona, HI
Vehicles
'23 R1S (x2); '22 R1T; '14 Jeep Cherokee
Clubs
 
Awaiting my (repeatedly delayed) delivery to HI….Wondering if anyone out there can share their experience with steep declines and crawl speeds. Basically, the access road I use everyday is a 1.4 mile poorly paved/rutted out 4WD-only road with an average incline of 25 degrees and a max incline of 45 degrees. Because I immediately pass through several 2-3 ft deep waterways after my decline, it’s critical that I don’t use friction brakes on my descent…lest I warp those hot brakes upon cooling in the water. Currently my 2014 Taco handles the work just fine in 4LO. Rivian has replied with cautiously optimistic enthusiasm in emails saying the decline holding capacity is actually inferior compared to Magna Steyr 4LO systems. But I certainly cannot afford to have a $75k hunk of metal delivered to me only to end up useless on my daily commutes into and out of the valley below. Looking for anyone who’s dropped their R1T down anything remotely similar to my steep situation. Thanks in advance.
Are you up working up on Mauna Kea, bruddah?

All Terrain Rock Crawl will limit speed to 20 mph. I think that’s the closest thing Rivian has to 4WD Low. That mode, combined with regen, should slow you down pretty well with minimal brake usage.

Funny, I was going to ask this same question with Mauna Kea Access Road in mind whenever I get closer to my planned R1S Hawaii delivery. There are a few Rivians in Hawaii already. I’m guessing owners took delivery in CA and shipped them over. I’ve read about multiple R1T sightings on Oahu, a handful on R1T’s in Maui, and my friend just sent me a picture of an R1S in Waimea on the Big Island. No Hawaii Rivian service available yet though.

Be glad they won’t deliver your car on island until service is available. My R1T on the mainland has needed some major repairs. Still absolutely love it, though!
 

Dark-Fx

Well-Known Member
First Name
Brian
Joined
Jul 15, 2020
Threads
96
Messages
9,358
Reaction score
17,746
Location
Michigan
Vehicles
Polestar 2, R1T, R1S, Livewire One, Fisker Ocean
Occupation
Engineering
Clubs
 
Are you up working up on Mauna Kea, bruddah?

All Terrain Rock Crawl will limit speed to 20 mph. I think that’s the closest thing Rivian has to 4WD Low. That mode, combined with regen, should slow you down pretty well with minimal brake usage.

Funny, I was going to ask this same question with Mauna Kea Access Road in mind whenever I get closer to my planned R1S Hawaii delivery. There are a few Rivians in Hawaii already. I’m guessing owners took delivery in CA and shipped them over. I’ve read about multiple R1T sightings on Oahu, a handful on R1T’s in Maui, and my friend just sent me a picture of an R1S in Waimea on the Big Island. No Hawaii Rivian service available yet though.

Be glad they won’t deliver your car on island until service is available. My R1T on the mainland has needed some major repairs. Still absolutely love it, though!
I thought rock crawl just wouldn't let you accelerate past 20 and if gravity got involved it would still go faster.
 
OP
OP

Hawaii Guy

Member
Joined
Mar 9, 2023
Threads
1
Messages
7
Reaction score
0
Location
Hawaii
Vehicles
NA
If you are at a high charge level (85+%), it won't regen very well, but in my experience the regen under that is typically amazing. Like, "brake-check" amazing. As long as you don't build up lots of speed, it will regen like mad, no way you'll use brakes. The only time I have to use my brakes is on the Autobahn, after going 100+mph, and trying to stop quickly and merge onto a ramp, it will lose some regen capacity from about 75-45mph. But downhill at a slow speed it should easily keep up the regen! I suspect but have not tried, that it would hold still even on a 45 decline due to regen and you will be forced to use the accelerator most of the way down. You should test drive one if possible... and be amazed..
Thanks rivian_germany!
Yeah, the regen alone likely won’t cut it here. Have road experience with my Model3, which IS impressive. Hoping one of the appropriate modes can hold. Have test drive set up, but they won’t take you off road. And nowhere equivalently steep anywhere nearby except SF…and that’s not in the test drive range.
 

Sponsored

OP
OP

Hawaii Guy

Member
Joined
Mar 9, 2023
Threads
1
Messages
7
Reaction score
0
Location
Hawaii
Vehicles
NA
Are you up working up on Mauna Kea, bruddah?

All Terrain Rock Crawl will limit speed to 20 mph. I think that’s the closest thing Rivian has to 4WD Low. That mode, combined with regen, should slow you down pretty well with minimal brake usage.

Funny, I was going to ask this same question with Mauna Kea Access Road in mind whenever I get closer to my planned R1S Hawaii delivery. There are a few Rivians in Hawaii already. I’m guessing owners took delivery in CA and shipped them over. I’ve read about multiple R1T sightings on Oahu, a handful on R1T’s in Maui, and my friend just sent me a picture of an R1S in Waimea on the Big Island. No Hawaii Rivian service available yet though.

Be glad they won’t deliver your car on island until service is available. My R1T on the mainland has needed some major repairs. Still absolutely love it, though!
Thanks shrink!
Yeah, that’s the best intel I’ve been able to get. And my route is into/out of Waipio Valley. Maybe I’ll grab one of those CA transplants and see if they want to visit the Valley!? Seen em around!!
Thanks again!
 

WSea

Well-Known Member
First Name
Patrick
Joined
Mar 6, 2022
Threads
39
Messages
1,589
Reaction score
1,898
Location
West seattle
Vehicles
R1T, Outback
Occupation
Architect
Each update has reduced the regen at beginning of leaving home for me down a steep hill and a couple of hairpins. This lack of regen or blending in and out happens even at 70 soc. Have tried charging for an hour before leaving and didn’t make much difference. The red low or no regen warning hasn’t come on after last update either. My recommendatio, unless future updates change this, is to take it slow. No experience with rock crawl on pavement but sounds like an option for you
 

HaveBlue

Well-Known Member
Joined
Nov 22, 2022
Threads
17
Messages
1,129
Reaction score
803
Location
91107
Vehicles
R1S DMP Max, Lifted GX470, APR Audi A7, BMW 325Ci
Clubs
 
As a side note, Toyota truck brakes "warp" not from heating cooling but from a combination of chronic issues, assuming everything in the suspension and tires such as loose components or out of round road force variations is fine. Cheap rotors and pads that don't self clean the deposits along with properly lubricating all sliding edges of the pads so they don't bind. Dual retraction springs also help the pads wear evenly so they don't bind. PowerStop or Brembo pads and rotors are a good start to getting rid the persistent issues that Toyota trucks have.
 

PowerBugs

Well-Known Member
First Name
Dru
Joined
Jun 13, 2022
Threads
24
Messages
147
Reaction score
137
Location
SF Bay Area
Vehicles
Toyota
If you are at a high charge level (85+%), it won't regen very well, but in my experience the regen under that is typically amazing. Like, "brake-check" amazing. As long as you don't build up lots of speed, it will regen like mad, no way you'll use brakes. The only time I have to use my brakes is on the Autobahn, after going 100+mph, and trying to stop quickly and merge onto a ramp, it will lose some regen capacity from about 75-45mph. But downhill at a slow speed it should easily keep up the regen! I suspect but have not tried, that it would hold still even on a 45 decline due to regen and you will be forced to use the accelerator most of the way down. You should test drive one if possible... and be amazed..
I just went to Half Moon Bay through hwy 92 and driving on AP Standard Regen under 60% SOC and I was surprised that during descent I didn’t have any Regen and have to use breaks. As I was on flat roads, I regain my Regen and noticed the same way back and saw the yellow lightning inside the circle icon telling me that there’s is no Regen on descent. This is something I haven’t observed before and probably new after the latest update.
 

rivian_germany

Well-Known Member
First Name
D-Rok
Joined
Dec 28, 2022
Threads
4
Messages
122
Reaction score
243
Location
Germany
Vehicles
'22 R1T, '22 M3LR, '09 Honda Odyssey
Occupation
Software Engineer
Clubs
 
OP - I would expect the regen to work much better at slow speeds/offroad because you are not pushing as much power back into the batteries. But on paved surfaces I would expect it to be weaker because you are building up a lot more momentum and trying to feed it back in. Your post described an off-road path, so in that case I would expect Regen to keep up. In the other cases mentioned here where regen failed, it seems they were on paved surfaces. Or did I miss something?
 

Sponsored

quartz

Well-Known Member
Joined
Jan 5, 2023
Threads
7
Messages
203
Reaction score
209
Location
Los Angeles, CA
Vehicles
Honda Clarity PHEV
Clubs
 
At 45°, you should be decelerating without breaks on high regen, assuming SOC is not high.
 

hungrycaterpillar

Well-Known Member
Joined
May 21, 2022
Threads
10
Messages
62
Reaction score
49
Location
Virginia
Vehicles
R1T
Thanks rivian_germany!
Yeah, the regen alone likely won’t cut it here. Have road experience with my Model3, which IS impressive. Hoping one of the appropriate modes can hold. Have test drive set up, but they won’t take you off road. And nowhere equivalently steep anywhere nearby except SF…and that’s not in the test drive range.
Rivian regen is notably stronger than Tesla.
 

shrink

Well-Known Member
Joined
Feb 16, 2021
Threads
67
Messages
1,050
Reaction score
1,868
Location
Phoenix, AZ and Kailua-Kona, HI
Vehicles
'23 R1S (x2); '22 R1T; '14 Jeep Cherokee
Clubs
 
I thought rock crawl just wouldn't let you accelerate past 20 and if gravity got involved it would still go faster.
You might be right but it says max
20 mph.

Rivian R1T R1S Steep Declines - avoiding friction brakes D9DA1E99-873D-43CB-AD76-BDCAAB6389FC


Waipio Valley is STEEP! Good luck!

Maybe reach out to Big Island Electric Vehicle Association? I’m officially a member but am not very active since I don’t have an EV on island yet. They might know the Rivian owner in Waimea.

https://www.bigislandev.org/
 

suprteck

Well-Known Member
First Name
Anthony
Joined
Dec 20, 2022
Threads
6
Messages
112
Reaction score
73
Location
California
Vehicles
Tesla Model 3, Rivian R1T
Occupation
Mechanic
I noticed when going down long mountain roads in warm weather and 60% charge I will lose regen and will have to use my brakes.
 

Aag12

Well-Known Member
First Name
B
Joined
Mar 17, 2022
Threads
26
Messages
307
Reaction score
378
Location
Denver
Vehicles
Na
I lose regen all the time driving down mountains in all weather scenarios. The characteristics of how/when have been changing with the recent updates. I will say that even when regen is cut down, there are still minimal regen levels so I don't gain speed. If anything it slows me down, slightly.
Sponsored

 
 




Top