Scorpion AS+ tire swap (from 20" Scorpion AT) - WOW big difference

[shrink]

(assuming 125 kw usable battery after the latest update)

According to a Munro battery breakdown, it’s actually 141.1 kWh capacity and 135 kWh usable - and the 2022.02.03 OTA reportedly increased the usable by a small unspecified amount.

https://www.batterydesign.net/rivian-r1t/

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[evguy]

Thanks for the info! To clarify, are these the new "Scorpion AS Plus 3"?

 

[Craigins]

The simplest way to get rivian to recalculate for the 21" is to find a friendly local rivian owner with the 21". Swap wheels and take it in to the service center for recalibration.

There are differences between the 20" AS and the 21" AS. Things like wheel weight and aerodynamics. I'm not sure how much they play into any calculations done by the onboard electronics.

 

[Scott]

If it were simply a matter of the tire diameter being adjusted to properly give range calculations and such then I am guessing Rivian would have the ability to adjust. However the rolling resistance and the weight likely play large factors. So it is much easier for them to say “we only tested with oem tires so that is all we support”

The speedometer is another story. That should be made accurate. Was it possible for your mechanic to make the speedometer readthe right speed?

 

[Condor]

I am planning on making the switch to AS tires as well.. Deciding between these and the Falken’s which are actually rated 116H.
Quesiton about range calculations though…. Is it really calculated on tire revolutions? I don’t understand why the vehicle wouldn’t cross reference GPS data.

 

[SEARivian]

Quesiton about range calculations though…. Is it really calculated on tire revolutions? I don’t understand why the vehicle wouldn’t cross reference GPS data.

Yeah I am wondering this too. Or just the fact that you know how long say your commute to and from work is, and surely you can manually calculate the efficiency at least to test it out and see if it's truthful.

 

[johnjohn]

My R1S was delivered with the 20 ATs - I would have preferred the 21s but got faster delivery by taking the 20 ATs. I just switched the AT tires for the Scorpion AS+ tires.

Big difference. Quick impressions:
1. Immediate 20% improvement in efficiency (adjusting for the fact that the car computer hasn't been recalibrate yet to adjust for the 3% circumference difference). Photo attached from my stop-and-go beltway traffic drive this morning.
2. Major drop in noise. Drone from ATs was getting very audible. These are silent.
3. Significant improvement in ride quality especially over larger bumps
4. Noticeable improvement in steering sharpness and highway tracking.
5. Overall, glad to have the forged 20 inch rims. But very glad I changed out the tires. My off road use is limited to when I take the driveway turn too tightly and take out the begonias.

Now what am I going to do with these giant AT tires in my garage...

These are the 275/70/20 tires. I had my longtime mechanic do the swap. Photos attached.

I am about to do the same but on my R1T. My OEM tires are soon due for replacement. Thanks for the info and I am looking forward to more efficiency!

Anyone use Tire Rack's mobile service?

 

[CrazyOne]

If this was a factory option, I would have paid for it. I wanted range, but also want the added smoothness of 20' wheels.

 

[JJE]

As you can imagine I have been thinking a lot about how to go about getting the car calibrated for the new tire size. There are no simple answers. I have a few thoughts on possible approaches. I would be interested in the reactions of the Brain Trust here.

Plan A is simply to have Rivian adjust the settings for tire size to reflect the AS 20s so the speedo is accurate. This I feel they must do.

Plan B. The range numbers I am seeing (after making adjustments for tire size) seem very close to what is being reported by owners of 21s. If I can somehow convince Rivian to calibrate the car to the 21 settings (and I have a half ass plan as to how to get them to do this - basically by asking them to put on a set of 21s at the service center, let me test drive, then put the 20s AS back on and not recalibrate) this should allow the car range estimates to be pretty accurate. I deeply doubt Rivian will do this but you never know.

Plan C would be the best option but is not currently offered. And that would be to let the car calculate the range estimates purely based on actual driving experience. This is not the way the current set up works. Certain variables are clearly fixed in the algorithm based on which "authorised" tire you are supposedly running. I can see this bc even after resetting, the range estimates are still the same standard 20 AT settings they were before (313 in conserve). Even though I am now getting an adjusted average of 2.6 mi/Kwh.

 

[ferdba77]

My R1S was delivered with the 20 ATs - I would have preferred the 21s but got faster delivery by taking the 20 ATs. I just switched the AT tires for the Scorpion AS+ tires.

I don't understand why you didn't just swap with someone who wanted the 20" w/AT tires. You could have asked for $2500 as well.

 

[JJE]

I wanted the forged wheels and the easy availability of 20 inch tires.

 

[goldburger]

As you can imagine I have been thinking a lot about how to go about getting the car calibrated for the new tire size. There are no simple answers. I have a few thoughts on possible approaches. I would be interested in the reactions of the Brain Trust here.

Plan A is simply to have Rivian adjust the settings for tire size to reflect the AS 20s so the speedo is accurate. This I feel they must do.

Plan B. The range numbers I am seeing (after making adjustments for tire size) seem very close to what is being reported by owners of 21s. If I can somehow convince Rivian to calibrate the car to the 21 settings (and I have a half ass plan as to how to get them to do this - basically by asking them to put on a set of 21s at the service center, let me test drive, then put the 20s AS back on and not recalibrate) this should allow the car range estimates to be pretty accurate. I deeply doubt Rivian will do this but you never know.

Plan C would be the best option but is not currently offered. And that would be to let the car calculate the range estimates purely based on actual driving experience. This is not the way the current set up works. Certain variables are clearly fixed in the algorithm based on which "authorised" tire you are supposedly running. I can see this bc even after resetting, the range estimates are still the same standard 20 AT settings they were before (313 in conserve). Even though I am now getting an adjusted average of 2.6 mi/Kwh.

D. Have someone with 21’s let you borrow them to take to the SC and have them calibrate to those….

 

[Riviot]

At the end of the day, you're truly getting better range and mileage, right? So computer buttons and widgets and calibrations aren't stopping you from realizing actual gains?

 

[Goose]

At the end of the day, you're truly getting better range and mileage, right? So computer buttons and widgets and calibrations aren't stopping you from realizing actual gains?

it’s not the realized gains OP is experiencing. The range calculations are off which can impact DCFC measurements and even preconditioning timing if on a road trip.

 

[Arky]

"Can you please recalibrate for the 21" wheel combo?"

"But those are 20s"

"Yes, can you please recalibrate for the 21s? just trust me"
?

It's a bit annoying because IMO I think the best tire selection is actually 275/55/R20 which doesn't match any size they sell. Like literally 5x the options with comparable load and speed ratings to OEM, and a pretty good match for mostly road use.

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