What is semi-active suspension in the R2?

[I95 Nightmares]

I'm thinking I want Premium, but I want to evaluate the differences compared to the Performance. The "semi-active" suspension is something I know little about. Questions:

1. What does "semi-active" mean? Adjusts damping but not height?
2. Is it involved in the additional drive modes available in Performance?
3. Is there any additional capability beyond just adjusting ride firmness, e.g. active roll control, etc?
4. Has anyone experienced this (in Austin or elsewhere? I'd be interested to know how much you can feel the difference)
5. Are there any reviews mentioning it?

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[Redline]

It's not an air suspension. It has active dampers.

 

[UnsungZero_OldTimeAdMan]

1. What does "semi-active" mean? Adjusts damping but not height?
2. Is it involved in the additional drive modes available in Performance?
3. Is there any additional capability beyond just adjusting ride firmness, e.g. active roll control, etc?
4. Has anyone experienced this (in Austin or elsewhere? I'd be interested to know how much you can feel the difference)
5. Are there any reviews mentioning it?

1. Damping adjustable shocks. Springs are what suspends a vehicle. Spring rate and length of spring determines ride height. Since the springs are traditional coil springs, not air, height is fixed, not variable. Shocks dampen, controls rate of compression and rebound motion; the up/down oscillation of chassis riding on those springs.

2. Most likely. Depends on specifics of software and how Rivian takes advantage of tunable hardware.

3. Damper firmness can also affect yaw and pitch. Can also be tuned to optimize handing & comfort while hauling cargo and towing.

Google Gemini summary of Wikipedia:​

Semi-active suspension is an intelligent vehicle damping system that adjusts shock absorber firmness in real-time (within milliseconds) based on road conditions and driving dynamics, optimizing for both comfort and stability. Unlike active systems, it does not add energy to the suspension but varies damping via solenoid valves or magnetorheological fluid.​

5. You won't see any in-depth reviews until a larger body if the press get their T&E units. The reviews that went out (like Doug DeMuro's) prior to 3/12 are more like previews—from a very small group Rivian invited. DeMuro and InsideEVs both covered handling in a general sense, that it drives incredibly well. IMO, ride/handling is probably the last thing to be concerned about.

 

[sparked]

1. Are there any reviews mentioning it?

The other problem is that all the early full reviews will be Performance models with semi-active suspension. Would we even see Premium Dual motor reviews until late in the year to compare the two? All we can do is speculate until then.

Maybe the 20" tires on the Premium dual somewhat offset the loss of semi-active suspension since those should have better ride quality than the 21"? I think Model Y Performance has semi-active suspension, but I can't find a lot of comparisons with the regular version.

 

[Zorg]

My understanding is that a semi active suspension allows for a softer more comfortable suspension at low speeds while firming it up at higher speeds. Wish it was available on premium version.

 

[ENVErider]

1. Damping adjustable shocks. Springs are what suspends a vehicle. Spring rate and length of spring determines ride height. Since the springs are traditional coil springs, not air, height is fixed, not variable. Shocks dampen, controls rate of compression and rebound motion; the up/down oscillation of chassis riding on those springs.

2. Most likely. Depends on specifics of software and how Rivian takes advantage of tunable hardware.

3. Damper firmness can also affect yaw and pitch. Can also be tuned to optimize handing & comfort while hauling cargo and towing.

Google Gemini summary of Wikipedia:​

Semi-active suspension is an intelligent vehicle damping system that adjusts shock absorber firmness in real-time (within milliseconds) based on road conditions and driving dynamics, optimizing for both comfort and stability. Unlike active systems, it does not add energy to the suspension but varies damping via solenoid valves or magnetorheological fluid.​

5. You won't see any in-depth reviews until a larger body if the press get their T&E units. The reviews that went out (like Doug DeMuro's) prior to 3/12 are more like previews—from a very small group Rivian invited. DeMuro and InsideEVs both covered handling in a general sense, that it drives incredibly well. IMO, ride/handling is probably the last thing to be concerned about.

Yep, I agree with this. The shorter answer is that the R2 will have dampers whose damping rates are controlled by the Rivian computer and/or an algorithm. Time will tell, but I'm fairly certain there will be different algorithms for different drive modes; that is the point of adding this to the suspension. Early testers have already commented on differences in feel between drive modes, beyond motor controller changes.
The R2 will not actively lift/lower or actively control roll, except by changing the damping rate (no hydraulic roll control like the R1).

 

[dleepnw]

Semi-active suspension is not new tech. There are a lot of vehicles that have this that are both on and off road focused. However, it being an known tech is good for Rivian and for us. Easier to service and should be cheaper to maintain than the air suspension, hydraulic roll control, and active dampers of the R1. Of course Rivian's implementation is its own so until someone has tested and reviewed it we don't know how it'll perform or feel. Some reviewers have commented that the R2 has a great ride, I think one said it felt better than the R1.

 

[RivianRiverRat]

Here is an older deep dive
R2 rear suspension has "incredible ride quality and handling" says RJ Scaring with preview photos

https://www.rivianforums.com/forum/...ng-says-rj-scaring-with-preview-photos.45770/

 

[funnynardo]

has there been any information if the premium has frequency selective dampers?

 

[UnsungZero_OldTimeAdMan]

has there been any information if the premium has frequency selective dampers?

Nope. But plausible. Clue is in Monroe's OEM parts catalog. Monroe is owned by Tenneco, which is a known supplier to Rivian.

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