Tire Sizes

[Ladiver]

Just for clarity, there is a Load Range, Load Index, and Speed Rating.

I can tell from the Rivian tire size 275/55R21 116H XL that this is a
- 32.9" Diameter
- 10.8" Width
- 6" Sidewall
- 103.3" Circumference
- 613 Revs/Mile
- 21" Wheel
- Passenger vehicle tire
- Maximum 2,756 lbs
- Maximum speed 130mph.

Load Range is the number of ply (for trucks) and max pressure

*Tire America and Yokohama Tire

Load Index is the Maximum Load Capacity

There is also a Speed Symbol representing maximum speed rating.

* https://www.yokohamatire.com/tires-101/how-to-read-a-sidewall-1/sizing-information


I suspect all of the popped tires are related to the fact Rivian is using a passenger tire and not a LT truck tire.

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[crashmtb]

I suspect all of the popped tires are related to the fact Rivian is using a passenger tire and not a LT truck tire.

All the flats were with the 20” all-terrains, which are LT275/65R20 and carry a load rating of E / index of 123

This tire size is quite common on HD pickups.

 

[Ladiver]

All the flats were with the 20” all-terrains, which are LT275/65R20 and carry a load rating of E / index of 123

This tire size is quite common on HD pickups.

Yep, I needed more coffee this morning. The 20's are LT Load Range E. That is the same rating I have on my Sierra 3500.

 

[Speedrye]

You guys sure about that? The stock AT tires aren't LT, they're just XL-load passenger tires if Pirelli is to be believed: https://www.pirelli.com/tires/en-us/car/catalog/product/scorpion-all-terrain-plus/275_65-r20

 

[thrill]

You guys sure about that? The stock AT tires aren't LT, they're just XL-load passenger tires if Pirelli is to be believed: https://www.pirelli.com/tires/en-us/car/catalog/product/scorpion-all-terrain-plus/275_65-r20

The text description is they're explicitly designed for the Rivians, and their Load Index is definitely in the LT area with 2756-lb per tire.

 

[SANZC02]

You guys sure about that? The stock AT tires aren't LT, they're just XL-load passenger tires if Pirelli is to be believed: https://www.pirelli.com/tires/en-us/car/catalog/product/scorpion-all-terrain-plus/275_65-r20

They are, even the link you gave says light truck and SUV. If you look for Rivian pictures where you can see the tires they have LT on the sidewall.

 

[crashmtb]

You guys sure about that? The stock AT tires aren't LT, they're just XL-load passenger tires if Pirelli is to be believed: https://www.pirelli.com/tires/en-us/car/catalog/product/scorpion-all-terrain-plus/275_65-r20

Silly me, the non Rivian version is an e rated LT.
The Rivian one indeed isn’t LT. load index 115

 

[Speedrye]

This is what made me wonder about LT- https://www.mavistire.com/tire-brands/pirelli/scorpionatelectric/2756520/4125700/

The listed XL rating only applies to passenger tires, not LT tires. I suspect they got the info from Pirelli, but who knows at this stage.

Also, if you zoom into the picture of the tire on the Pirelli site, the tire size does NOT have LT in front of it. I wonder if they were using the heavier E-range tires on trucks for testing before Pirelli got them the production tires. I'll bet the lighter XL tires would be better on range than those. I can't find where I originally found the 48lb weight for the AT tires anymore.

 

[SANZC02]

Silly me, the non Rivian version is an e rated LT.
The Rivian one indeed isn’t LT. load index 115

Interesting, Went back and looked at more pictures. Seems like the earlier pictures had the LT on them the later ones do not.

I assume the earlier ones were not the Rivian designed ones.

That will teach me to respond without doing more research.

 

[crashmtb]

This is what made me wonder about LT- https://www.mavistire.com/tire-brands/pirelli/scorpionatelectric/2756520/4125700/

The listed XL rating only applies to passenger tires, not LT tires. I suspect they got the info from Pirelli, but who knows at this stage.

Also, if you zoom into the picture of the tire on the Pirelli site, the tire size does NOT have LT in front of it. I wonder if they were using the heavier E-range tires on trucks for testing before Pirelli got them the production tires. I'll bet the lighter XL tires would be better on range than those. I can't find where I originally found the 48lb weight for the AT tires anymore.

I wonder if rivian’s version isn’t built off of the 275/60R20 scorpion AT, which weighs 47lbs per tire rack spec sheet.

Figure the taller sidewall adds that extra pound, remembering that tire weights are nominal.

 

[Ladiver]

I thought Rivian had said LT early on. If they switched to passenger tires, then my comment in the first post stands. Passenger tires are not great at resisting rock puncture. They can hold weight but are not as durable. If they are not LT, I know my first upgrade.

 

[crashmtb]

I thought Rivian had said LT early on. If they switched to passenger tires, then my comment in the first post stands. Passenger tires are not great at resisting rock puncture. They can hold weight but are not as durable. If they are not LT, I know my first upgrade.

The pirelli gobbledegook mentions adding “a light truck compound“ to the sidewalls, whatever that means.

 

[Autolycus]

Here's a screenshot from JRE's video from Breckenridge. He's the one who blew his tire. I couldn't find a clean shot of the tire he gashed, but I assume it's the same type as the spare. I do not see LT marked anywhere, but maybe it's in smaller print or in the shadow.

 

[Ladiver]

Looks like LT is out and passenger vehicle is in. This definitely explains why on-road performance is sporty and responsive. I'm sure they did this for ride quality and noise as well. Not a bad option, but for those going off-road (rocks) you will want LT tires or you have a much higher likelihood of having a blowout, as we saw in the reviews.

 

[Speedrye]

Looks like LT is out and passenger vehicle is in. This definitely explains why on-road performance is sporty and responsive. I'm sure they did this for ride quality and noise as well. Not a bad option, but for those going off-road (rocks) you will want LT tires or you have a much higher likelihood of having a blowout, as we saw in the reviews.

I suspect weight was the biggest factor. There's a range/weight penalty jumping to a real, LT, all-terrain tire. I'm a little surprised by the quoted 10%-15% loss from their street 21's to their AT 20s. Having upgraded tires in the past on ICE vehicles, I've found I lose about 3% going to a 10-15lb heavier tire, and about 5% going to an inch taller+heavier tire. I've lost a full 10% by increasing tire weight 20+lbs and gaining 3" in diameter though, but we're only talking an inch difference in tire height and 10lbs of weight with the R1x.

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