Growing efficiency Gap: R2 w/ 21" vs. 20" tire sets

[DaveA]

Your R1T tire pressures belong in another thread. I believe R2's recommended pressure is 42 psi.

This is for my R2 w 21s.

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[windshieldfarmer]

It's either delusional or wishful thinking to believe the 20" AT has more range efficiency than the 21" AS. Just look at the official Rivian numbers - 330 mi on 21" AS and 307 mi on 20" AT. This thread is badly conceived.

Perhaps….though it is interesting Kyle at OOS extrapolated 253 miles range at 70 mph on 21”s and Tim (Colorado guy) saw over 260 miles range at 70 mph on the 20” All Terrains. Colorado air is thinner but Tom also had to climb 2,000, the effects of such won’t be totally offset by the subsequent 2,000 decline in elevation. While counterintuitive the 20” tire wheel combination might have less drag losses relative to the 21” as speed increases. Don’t know but a side by side test would be interesting; something no one has done. I wish OOS had done that when they had the opportunity.

 

[UnsungZero_OldTimeAdMan]

Perhaps….though it is interesting Kyle at OOS extrapolated 253 miles range at 70 mph on 21”s and Tim (Colorado guy) saw over 260 miles range at 70 mph on the 20” All Terrains. Colorado air is thinner but Tom also had to climb 2,000, the effects of such won’t be totally offset by the subsequent 2,000 decline in elevation. While counterintuitive the 20” tire wheel combination might have less drag losses relative to the 21” as speed increases. Don’t know but a side by side test would be interesting; something no one has done. I wish OOS had done that when they had the opportunity.

But are their driving routes, styles/habits, ambient temp, wind, pack tempts and average speed identical? There are how many posts/threads arguing over efficiency? Still only one thing is known for certain: EPA-certified figures almost never reflect all real world results. Too many variables involved. ICE or otherwise. It’s mostly a formality for sake of governance and job security for the career paper pushers. Just drive/enjoy the cars, IMO. Better if time spent advocating and voting for charging infrastructure improvements.

 

[windblowlc]

This is for my R2 w 21s.

51 psi is the maximum tire pressure this tire could be pressurized cold. It's not the Rivian recommended pressure for the R2. 42 psi is.

 

[DaveA]

51 psi is the maximum tire pressure this tire could be pressurized cold. It's not the Rivian recommended pressure. 42 psi is.

Yes, I'm aware. This would be an experiment to see if higher psi would help range during highway driving.

 

[windblowlc]

Yes, I'm aware. This would be an experiment to see if higher psi would help range during highway driving.

Why would you want to do that even if it's for the sake of range experiment? A couple of psi higher I could understand, but at max 51 psi?

 

[ksurfier]

Tires might blow up!!

 

[blipit]

OOS of spec actually had both sets available when testing. They should have done a 20" all terrain test. Probably ran out of time.

 

[TechDad]

OOS of spec actually had both sets available when testing. They should have done a 20" all terrain test. Probably ran out of time.

Or it didn't fit their 'narrative' to get more clicks

 

[sixmile]

Kyle and Jose addressed this. The 21s were broken in but the 20’s weren’t. He said they don’t test tires that aren’t broken in. Jose said he would do a range test with the 20s after he drove back to Florida.

 

[blipit]

Or it didn't fit their 'narrative' to get more clicks

Jose's R2 came with 20 all terrain. OOS/Jose asked Rivian to provide a set of 21" wheels/tires so they could have the best possible setup for range testing...so they thought.

I just think there needs to be more testing done all around.

 

[SuperFeisty]

Does anyone know of all the current available tires for the 20 inch wheels, which ones have the most range or lowest rolling resistance? I don't see anything specifically mentioned on Tire Rack. I'm willing to sacrifice the worse range 20' AT tires if the next non OEM tires are even more efficient than the 21' Pirellis.

 

[ribuck97]

Let’s just state the obvious…. The 20” 100% get more range because of wheel design and more importantly, because BFG >>> Pirelli

 

[csun22]

Is anyone considering getting the 20" wheels but swapping them from AT to AS when new tires are needed or sooner? I saw a video a couple of weeks ago from Travis Ketchum where he showed the variety of options for 20" tires whereas there is currently only one option for replacing the 21" tires.

I don't think I would benefit from AT tires, but if there are more options, and it's cheaper (as of now) to potentially replace 20" tires, I would consider getting them just have more options down the road especially if I can get AS and maybe get a little more range out of them.

My order window is in October/November and I originally thought I would want the 21" wheels. The 70mph range tests were a little disappointing for me, but I'm still planning on placing my order when it's my turn but I'm now considering 20" wheels.

 

[Redmond Chad]

I did that with my R1S, for similar reasons. I got the 20" AT wheels, sold the tires and put AS tires on.

I liked the wheels, and the new AS tires were pretty good. But it cost money (I had to pay more for the new tires than I was able to sell the old ones for), took time, and by the time I'd need new tires - nowhere near that yet - there were more options.

So I ordered the 21's on my R2. I prefer the slight edge in handling, ride should still be good with all that sidewall, I saved money (though I may spend it later on tires), they'll already have AS tires so I don't have to swap, and as the R2 is higher volume than the R1 I suspect we'll see more tire options sooner. But who knows.

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