Ride comfort 20 vs 21

[LL75]

I think the BIG problem of the 21” setup is that the rim is reported to weigh something like 48 pounds. Adding the 37 pound tire means it’s a total of 85 pounds vs ~62 pounds for the AW 20” rims plus grabber HTS, wheel weight has about half the impact as tire weight (rotational inertia, ie distance from rotational axis), tire rolling resistance between the tires are likely different…all in all it’s not that surprising that 275/60R20 (20”) is more efficient than 21” setup…is it?

That is probably half of it. Although tires with better rolling resistant would be more efficiency in combo with the atomic wheels weight. The stock pirelli 21" supposed to be one of the best with rolling resistant

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[jemkewl]

2.77 on stock 21" is insane. I swapped my 21" at 16k miles and my lifetime is at 2.29 with about 90% all purpose drive. I'm currently runs the same set up as you but with general grabbers hts 60 and according to limited number from electrify, im getting around 2.5 all purpose with this 80 degree temperature. When I first switched , it was around 2.0 but the weather was a little cold and tires was sticky.

Mostly flat travel around southeastern PA area. Always make sure my tires are 48 psi cold and 50 to 51 psi hot. My factory alignment seems to be pretty good. Probably 40% highway and 60% local road travels. About 75% all purpose and 25% sport mode. I've used the brakes like 5 times. Gradual stopping VS abrupt stopping 99% of the time. Garage kept at home - insulated garage, not heated, but heated/cooled living space above garage.

 

[UnsungZero_OldTimeAdMan]

The people reporting the best results seem to be running the 20 inch brights

That is quite the claim. This is a joke right? Ride quality has everything to do with tire construction (the sidewalls specifically), air volume and air pressure. Nothing to do with finish or style of the wheel. Efficiency between 20/AT and 21/AS is a foregone conclusion. ATs are less efficient because higher rolling resistance—because of softer/grippier rubber compound and the larger gaps between tread block, which gives it more bite on soft terrain but also make it less round.

 

[ATL_Canes]

Wow, there's a lot of back-and-forth in here and it makes my head hurt a bit. I had the 20" ATs on my first truck, and am about to take delivery of a truck with 21s. I don't drive off-road (had all sorts of intentions the first go-round, but being realistic I'm just a road warrior). The thought was to maximize driving comfort and efficiency, knowing that replacement options are limited (even though I prefer the look of the 20s on this truck). I go from feeling good about the decision to dreading it, depending on which post I read.

 

[racekarl]

That is quite the claim. This is a joke right?

I'm not sure it was entirely meant as a joke, and I think it may have been meant entirely in regards to efficiency.

The 20" wheels are forged vs. the cast 21" and 22" wheels and ought to be significantly lighter, in addition to smaller diameter wheels being more efficient. The Bright and Dark wheels have a smoother surface profile and are presumably more aerodynamic than the default 20" wheels.

Who knows if it adds up to anything in real life, but on internet message boards, the 20" Bright and Darks should be the most efficient wheels, ceteris paribus.

 

[140 degrees]

I'm not sure it was entirely meant as a joke, and I think it may have been meant entirely in regards to efficiency.

The 20" wheels are forged vs. the cast 21" and 22" wheels and ought to be significantly lighter, in addition to smaller diameter wheels being more efficient. The Bright and Dark wheels have a smoother surface profile and are presumably more aerodynamic than the default 20" wheels.

Who knows if it adds up to anything in real life, but on internet message boards, the 20" Bright and Darks should be the most efficient wheels, ceteris paribus.

Exactly what I was trying to express. That part of my post was about efficiency, and you put it more clearly than I had. Thanks!

 

[moondoggy]

I had my 2022 Rivian R!T with 21 inch tires in for service yesterday (windshield replacement and tire rotation). They gave me a loaner R1T with 20 inch AT tires on it. When I first started driving the loaner down the street at 30 mph I thought something was wrong with it, there was so much noise and vibration, then I realized it was the tire distance. I only drove it about 15 miles, including some short freeway time, but that was enough to convince me to never get that 20 inch tire. I'm sure they are better when new but wow, I could not stand the noise of those 20 inch tires. Not sure how many miles they had, but there was definitely plenty of tread life on them when I checked. So if you like a quiet vehicle, like me, then go with the 21 inch tires, unless you really need the off-road ability and are the type to be unaffected by loud tire noise.

W/ R1S I had this same experience and much prefer the 21s. In addition to a drastic noise difference, I find the stability at highway speeds to be far better on the 21s.

 

[ksurfier]

This is extremely interesting, most with an off-road monster like the R1 are looking for 16-18 inch rims to bring a big fat tire to off-road and absorb the bumps. Unfortunately the brake calipers will only let 20” rims be used. It’s possible the 21” setup survives and people seek it out, who knows…

 

[CrazyOne]

I had a loaner with 20s and it had a constant rumble and slight vibration in steering. I am sure you will get used to it, but it's there. 20s are better on larger potholes, and the feel was missing in corners.

At same price, I would get 20s with AS. I don't think it's worth spending 4k more. If you drive a lot, they may payoff on the long run. Personally, I would keep the money and use it for another project

 

[CrazyOne]

My early 2022 was equipped with 20" ATs. My new Max Pack that I picked up today is on 21" wheels.

The 21's are much, much quieter and have a slightly better road handling feel. The 20's are somewhat softer and are likely more capable.

The 21's are expensive to replace as there is only one option (with a second coming soon) but the 20's were wearing much quicker than I hoped. I replaced the OE set with 13k miles on them because they absolutely roared. I fully expected to not get out of the teens with the replacement set too.

What other option is coming soon for 21s?

 

[MidnightRivian]

20” is more forgiving thanks to the sidewall and last longer but tend to get noisy around 15,000 miles. Range is reduced for sure unless you swap from 20” all terrains to 20” all seasons.

21” has better handling and tend to be quiter but not as forgiving compared to 20” on rough roads. Best range option with 21” but only one replacement tire option.

 

[LL75]

What other option is coming soon for 21s?

michelin defender LTX M/2 . Probably summer of this year

 

[Lansorep]

I find the 20” ride better, or make the bumps a little softer and it feels more springy. The 21” allow the r1T to turn more tightly and use less energy to drive long distances.

 

[jemkewl]

michelin defender LTX M/2 . Probably summer of this year

Fingers crossed, but they said that last year too...

 

[MMRivian]

Correct, the 20” General Grabber HTS60 (275/60R20) is equal to or more efficient than 21” OEM. Riviot, LL75, JJE, ajthonysfl, and many others have data to confirm. Other than wearing out very quick and being expensive, not sure what the key attributes of the 21” tire are.

These tires do not seem to be available in the R1T size. Nor is there any all season in this size on the tire rack site.

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