Let's remove the Conserve Mode stigma

[Ecupip]

Maybe Rivian will one day update conserve mode to use the rear motors (in addition to the fronts) at low speed

I was just thinking this also. Why can't they reprogram conserve mode to act the same as the duals?

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[evguy]

Rivian said that the dual motor will switch to one motor automatically on highway. From testing others have done on this forum is a large part of the difference between dual and quad EPA numbers.

Therefore for everybody who is avoiding use of conserve because of tire wear, I don't see why there would be any difference between a dual motor automatically disengaging the rears versus a quad motor in conserve **if** set at standard right height.

I've started using conserve on hwy trips over 20 mi once the car is up to speed but have conserve set for standard ride height. Anyone else doing the same?

I do the same and my tires are holding up well after 17,000 miles.

 

[mikehmb]

Rivian made some s/w changes recently to minimize the potential damage caused when decoupling the rear mechanical disconnects when switching to/from Conserve.

Go out on the highway, find a spot that’s smooth and without many cars (to avoid distractions), and switch it on. You’ll notice a barely perceptible change of power while the software unloads the rear axles. Siimilar when you turn conserve back off.

I’m not 100% sure when this was implemented, but there was a marked change in what I heard and felt when switching Conserve on/off at highway speeds some time in the last 6-8 months. I could hear and feel the disconnect locking into place last year. Not anymore.

 

[CrazyOne]

Quad uses dog clutch to engage rear wheels. I believe this is not robust/smooth enough to do several hundred times on a drive.

Not sure what dual uses. If it's a normal clutch, it can engage and disengage many times during a drive. Most AWD cars have wet clutch which does this several times during a drive. The actuation feels like it takes a fraction of a second in my other cars.

Wet clutch is problematic when difference in speeds is high, as motor is completely stopped. Rivian likely uses a dry clutch on dual.

Tldr, conserve in quad is very different from dual motor.

 

[EmPickle]

Quad uses dog clutch to engage rear wheels. I believe this is not robust/smooth enough to do several hundred times on a drive.

Not sure what dual uses. If it's a normal clutch, it can engage and disengage many times during a drive. Most AWD cars have wet clutch which does this several times during a drive. The actuation feels like it takes a fraction of a second in my other cars.

Wet clutch is problematic when difference in speeds is high, as motor is completely stopped. Rivian likely uses a dry clutch on dual.

Tldr, conserve in quad is very different from dual motor.

About here they talk about the new disconnect and the differential in the dual motor and then compare it to the "dog-clutch" (Monroe video's words) in the quad.

There's an electromagnet that pulls on a spring to engage or disengage a gear. I imagine this will be a much smoother transition.

This is the system in the quad (which apparently is not called a dog-clutch)
https://www.sae.org/news/2022/06/amsted-driveline-engineering

Claimed activation of 20ms. I wonder how many times it can engage. I always try to engage it when I don't have a lot of torque in the system just in case.

 

[CruxOp]

Rivian made some s/w changes recently to minimize the potential damage caused when decoupling the rear mechanical disconnects when switching to/from Conserve.

Go out on the highway, find a spot that’s smooth and without many cars (to avoid distractions), and switch it on. You’ll notice a barely perceptible change of power while the software unloads the rear axles. Siimilar when you turn conserve back off.

I’m not 100% sure when this was implemented, but there was a marked change in what I heard and felt when switching Conserve on/off at highway speeds some time in the last 6-8 months. I could hear and feel the disconnect locking into place last year. Not anymore.

That makes a lot of sense. We got our s at the end of July and don't have a ton of miles on it but I've noticed it's very smooth shifting in and out of conserve on highway. Likely synchronizing the speed of the electric motors to the axle before engaging the clutch.

 

[Jabbahop]

It would have to be a hardware change since the rear motors are the only ones with mechanical disconnects. For various reasons Rivian geared the front motors taller than the rear, so running the fronts at speed is more efficient. They continued that with the dual motor even though the design of the Enduro drive unit allows more seamless engagement, so I don't see them changing this in the future. So we're stuck with FWD.

That all said, OP's point of using Conserve on the highway at Standard height is relevant. But you again don't have 4WD when engaged regardless of how much you push the skinny pedal. It's still probably best used if you think you might not reach the next charger...but then you can just slow down a bit too. The aero impact of speed will still have more of an effect on range than dropping out two motors. According to Munro, it's probably no more than 6%, which tracks with Rivian claiming just over 300 miles for a Quad+Large with 20s in Conserve mode vs 284 EPA in All-Purpose. As someone else said, with DCFC being 150-220 kW (and 300-400+ mi per hour of charging), you're better off driving the speed you want and arriving at low state of charge because you'll always be able to charge faster than you can drive.

Except if you have to rely on EA ;-)

 

[Si.LE.R1S]

This is an interesting thought.

I will be getting my R1S any week now, and I've decided to just use all-purpose after seeing all the tire issues. I will do longer trips to the cabin and back, and conserve in standard height might be the ticket. I'd be curious to see people test this and what the efficiency might be vs all-purpose.

Have been doing this since I switched to stock ATs for past 1000 miles:

600 mi road trip conserve, standard height, 70 mph cruise
400 mi typical around town short freeway runs all-purpose standard height

overall 2.11 mi/kWh, or 285 “range” on stock ATs, a little better than EPA. Too soon to check for any measurable uneven wear, though.

 

[HokieBird7980]

At the end of the day, conserve only gets you about 10% better mileage at the time you turn it on and off of all purpose. So, at full charge on Conserve, my R1T says 314miles and in all purpose full charge 284, so 30 miles at that point. If i were to wait until i'm getting low in range prior to getting to a charger, say with 50 miles left of range, and then switch to conserve, you're only going to get 5 extra miles of range. Therefore, i don't use it at all, even on long trips and plan the stops for chargers to be more or less like you would in an ICE vehicle...ie don't let it get to E.

As to tire wear, i have 18,500 miles on the R1t 20's and have never rotated the tires! I took it to Atlanta for service this week and will have them rotate now, but checked on way down and they were 7 on the front, 8 on the back, so still have plenty of tread and no uneven wear. Over 95% of my driving in all purpose standard height. Actually hated the "auto" height adjustment when it came out and it seemed to get me less mileage that keeping R1T in all purpose standard height.

 

[iansriv]

I'd be curious to see someone test all these settings on a highway and find out which setting and speed is most efficient, and then figure out what the loss might be in standard height, to save your tires.

There's a plethora of online review but none testing what you suggest. I think that's a great idea!

 

[ElGuapo]

Can someone submit the question to Rivian for their weekly responses on Reddit? Seems like they should be able to answer it.

I don’t use conserve, but have turned it off and on at times just to test it and haven’t heard or felt anything.

I DO use auto ride adjust because I use AP mode and it’s easier and more efficient for it to lower on the highway. We shouldn’t have to do any of this stuff manually or Rivian made a mistake. If you pay $80k for a car, drive it how you want to drive it. Especially while it’s under warranty. And enjoy it!!

If Rivian didn’t want us changing it while driving, they could easily remove that option - they didn’t and they don’t give a warning, so I think it’s fine.

That said, I think it best to use conserve only if you need it for a trip. Otherwise, having AWD is preferable for many reasons.

As for wear, unless Rivian says something, it’s really hard to have a true feel for this as you’d have to drive thousands of miles in conserve only in various conditions, etc.

 

[Dark-Fx]

I was just thinking this also. Why can't they reprogram conserve mode to act the same as the duals?

The design of the mechanism for the quad shouldn't be used under load. The dual motor mechanism can be. It's not just because of the mechanism difference but the amount of tolerance of misalignment when engaged. Dual motor looks to be maybe a few degrees of motor rotation differential during engagement, but the quad is easily 45 degrees or more, and Rivian doesn't have the necessary precision in timing to do the engagement under load in the quads. You will break something eventually if you need to suddenly accelerate hard.

 

[LL75]

At the end of the day, conserve only gets you about 10% better mileage at the time you turn it on and off of all purpose. So, at full charge on Conserve, my R1T says 314miles and in all purpose full charge 284, so 30 miles at that point. If i were to wait until i'm getting low in range prior to getting to a charger, say with 50 miles left of range, and then switch to conserve, you're only going to get 5 extra miles of range. Therefore, i don't use it at all, even on long trips and plan the stops for chargers to be more or less like you would in an ICE vehicle...ie don't let it get to E.

As to tire wear, i have 18,500 miles on the R1t 20's and have never rotated the tires! I took it to Atlanta for service this week and will have them rotate now, but checked on way down and they were 7 on the front, 8 on the back, so still have plenty of tread and no uneven wear. Over 95% of my driving in all purpose standard height. Actually hated the "auto" height adjustment when it came out and it seemed to get me less mileage that keeping R1T in all purpose standard height.

This is what i noticed as well. I took my car to get rotation at 7k miles as folks on here recommended. Discount tires said all my tires are wearing evenly. 90% in all purpose mode. Since this is the case, is there a reason to do tires rotation?
On your other note, why would auto height get less mileage? Wouldn't lower the height when driving on highway give more aerodymic?

 

[UnsungZero_OldTimeAdMan]

I don't see it as a stigma. Engineering is a game of compromises. Quad was designed AWD performance as its primary objective. Therefore, not optimized for FWD and ultimate efficiency. Knowing that, and understanding suspension geometry—with added complication of variable height—and its affect on camber, toe, caster and tire wear, there is a price to be paid for sake of efficiency. And understanding these things can help you understand how and when best to use Conserve. The stigma comes from folks who don't spend time understanding the whys, won't listen to explanations, and are quick to blame Rivian for short tire life.

 

[ads75]

An additional 10% range for half the power…no thanks. Potentially more tire wear, there go “cost” savings. I doubt many people need that extra 10% energy/cost savings if they paid $80k for a vehicle. If I wanted a 400hp truck I would’ve bought something else. For my use, that extra 30 miles will rarely, if ever, make a difference. If I was that concerned about energy efficiency, I should’ve bought something else.

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