Range Against the Machine¹ - Rivian OEM Wheels, Tires, and Range Considered

[kanundrum]

Here is a highway run with a 13 mile an hour cross wind, low setting, 47 psi in all purpose mode. Used driver+ 70mph on main stretches.

Sponsored

 

[michiganpinball]

Great analysis. I would also contend that weight has a significant factor on range. On my Tesla Model 3 performance I switched to 18 inch wheels (stock is 20) and lowered the weight of each wheel/tire combo 10 pounds. So 40 pounds overall. Rotating unsprung weight is the worst for performance/economy. I kept the overall diameter the same and the tread was very similar as both tires were summer performance. This change alone took 2 tenths off 0 to 60 times (3.5 to 3.3). My estimate is it added 5% to 8% range. Since I did this early on and that car has 130k miles this saved quite a bit of electricity overall.

Others in the Tesla community do this swap purely for performance. A lighter wheel tire yields faster acceleration, better braking, and better cornering as well as better efficiency. It really is the #1 thing you can do for overall goodness. Of course you need to keep the wheel strong enough for your needs. Track racers will spend big $$ on forged wheels for maximum performance.

While not usually as important for a large truck/SUV, lighter tire+wheel weight has the same effects. Lighter equals better performance and economy. I plan on weighing the wheel/tire on my 2025 R1T Dual to see where we are at. If I can save 10 to 15 pounds per corner at a reasonable price I will make the switch.

This was a trick I have used on many of my ICE cars in the past to eek out some performance and efficiency gains. It was cheaper than trying to add horsepower. And adding horsepower doesn't help with braking and handling.

 

[ksurfier]

Great analysis. I would also contend that weight has a significant factor on range. On my Tesla Model 3 performance I switched to 18 inch wheels (stock is 20) and lowered the weight of each wheel/tire combo 10 pounds. So 40 pounds overall. Rotating unsprung weight is the worst for performance/economy. I kept the overall diameter the same and the tread was very similar as both tires were summer performance. This change alone took 2 tenths off 0 to 60 times (3.5 to 3.3). My estimate is it added 5% to 8% range. Since I did this early on and that car has 130k miles this saved quite a bit of electricity overall.

Others in the Tesla community do this swap purely for performance. A lighter wheel tire yields faster acceleration, better braking, and better cornering as well as better efficiency. It really is the #1 thing you can do for overall goodness. Of course you need to keep the wheel strong enough for your needs. Track racers will spend big $$ on forged wheels for maximum performance.

While not usually as important for a large truck/SUV, lighter tire+wheel weight has the same effects. Lighter equals better performance and economy. I plan on weighing the wheel/tire on my 2025 R1T Dual to see where we are at. If I can save 10 to 15 pounds per corner at a reasonable price I will make the switch.

This was a trick I have used on many of my ICE cars in the past to eek out some performance and efficiency gains. It was cheaper than trying to add horsepower. And adding horsepower doesn't help with braking and handling.

Agree 100% - this has been my same experience over hundreds of thousands of miles with Teslas and now 20,000+ with a R1S

 

[tps5352]

Further Thoughts on Increasing
Driving Range in R1S and R1T​

Background - Where's the Proof for Claims Made in Original Post #1?

The OP #1 (cheekily) advocates for higher-profile, road tires on smaller (20") wheel-rims (as opposed to lower-profile tires on larger 22" wheel-rims, as Rivian seems to be doing) as a means to maximize range (as well as road comfort, tire durability, etc.).

Yet definitive proof for this (potentially heretical) idea is lacking. Why?

Simple. It’s a big deal--expensive and time consuming--to decisively evaluate range among different wheels/tires. No individual driver--especially one not receiving adequate compensation--can reasonably be expected to expend the kind of resources necessary to ‘scientifically’ determine which wheel-sets result in the best range.*​

And unfortunately, we cannot necessary rely on the tire industry and the automotive media. Tires are consumable auto-parts that (a) are absolutely necessary, (b) often have to be replaced multiple times in the lives of most vehicles, and (c) are relatively-expensive. As a result, tire production and sales is a multi-billion-dollar, highly-competitive industry.​

As Rivian drivers know, tire prices vary wildly (and sometimes seemingly inexplicably) among brands and even among different sizes of the same tire-models. (Tires sometimes seem like commodities, with prices set or fluctuating based on supply-and-demand and what is in-fashion rather than being strictly determined just by production costs and overhead alone.) Bottom line: It can seem difficult to find truly unbiased and comparable published tire-test results.​

Suppose someone did want to attempt to accurately test the effect that Rivian wheel and tires sizes have on maximum range; what is involved?

Variables that should be held reasonably constant during testing include:

• The test vehicles--use of the same model-version, in the same condition, and preferably the exact same test vehicle.
• The driver(s)--the same driver, where possible.
• Weather--e.g., dry pavement, similar ambient temperatures and wind patterns, and so forth.
• The test 'track' or route.

And importantly (yet frequently violated):​

• The tread design (pattern, depth) and tire architecture (number/type of layers, rubber composition, wall thickness, etc.)—in other words, testers should try to use the same tire model (but in different sizes).

In an ideal test (of wheel/tire sizes on range), only wheel diameter and tire sidewall height (not the width or total tire diameter, and not the tire brand or model) would vary. (As we’ll see, this is easier said than done.)

Unfortunately, these test requirements create difficulties. When wheel/tire sizes are purposefully changed, it is usually with a different intended purpose in mind, and therefore the tread design and tire construction usually changes also (which can prejudice the outcome and invalidate resulting conclusions).

Think about it. How many Rivian drivers maintain two sets of differently-sized wheels outfitted with the same model of tires? Probably none. Most drivers who bother to maintain two or more sets of wheels of different sizes probably do so for different intended purposes (e.g., summer versus winter conditions; on-road versus off-road travel; etc.). So not only do wheel and tire sizes differ, but tread design and rubber compositions also tend to be different. Therefore, some conclusions reached after range evaluations can be legitimately questioned (for example in the case of this highly-viewed online range evaluation).​

Proposal for Experimentation

Assuming that all this is true, how could a driver theoretically evaluate range in an unbiased manner? How about using a single tire model that (a) meets Rivian factory OEM size and load requirements and (b) is available for both the factory 20-inch and 22-inch wheel sizes. (Not so easy to do, as we will see.)

For this hypothetical experimental test design, I will ignore Rivian’s (Gen 1) 21-inch wheel and (Gen 2) 33-inch (275/60R20) tire. That leaves the following wheel-sets to be compared:

• 20-inch (OEM) wheels with 34-inch (275/65R20) tires
• 22-inch (OEM) wheels with 33-inch (275/50R22) tires

These wheel-sets (a) stay within the Rivian factory OEM playing-field, (b) represent current wheel/tire sizes for most unmodified Gen 2 vehicles and, I believe, (c) provide the largest difference in sidewall height (≈profile) between two stock Rivian OEM tires. (So they stand the greatest chance of revealing a range difference if my premise has any merit.)​

Rivian Gen 2 Wheels & Tires (from OP #1).
(Note sidewall measurements.)​

As stated above, theoretically we would want to use the same brand and model of tire—i.e., the same tread and over-all tire design—for both wheel-sets. (Naturally we would also want all tires tested to be undamaged and without repairs, be inflated to the factory-recommended pressures, and have approximately the same level of wear, if any.)

So, under these restrictions, what test tires should/could be used? Here's where things get dicey.

What Tires to Test? - First Consideration

I choose to limit options to the following:

• Tires listed in the Rivian Tire Guide.
• Rivian factory OEM wheel and tire sizes.
• Tires with a Load Index of 116 or greater.
• 275/65R20 (34” diameter) versus 275/50R22 (33”) tire sizes.
• “All-Season” (AS) tires only.
• No 3PMSF (a winter-condition designation) tires.

Results:

• No one Rivian-appropriate AS tire model is available that fits both 20-inch and 22-inch wheels.
• While there is a Michelin “Defender” tire model that fits 20-inch wheels and another one that fits 22-inch wheels, unfortunately the tread design of the two "Defender" tires appears significantly different. Too bad.

Michelin Defender LTX Platinum tread (275/65R20)​

Michelin Defender LTX M/S2 tread (275/50R22)​

By the way, including 3PMSF-designated tires does not seem to increase the number of potential tire candidates.

Second Consideration

As we know, Rivian R1 vehicles are relatively heavy and designed for off-road-related recreation. While such tires are not intended to provide maximum range, suppose we look at 34- and 33-inch all-terrain (AT) tires intended for 20- and 22-inch wheels?

Results:

The available selection includes many 34-inch AT tires (for 20" wheels), but almost no 33-inch equivalent AT tires (for 22" wheels), with one exception:

• The BF Goodrich All Terrain T/A KO3 (available for both 20” and 22” wheels).

Although use of an all-terrain tire may not result in maximum range, it could provide an interesting test of the effect of wheel/tire size on range. Let’s keep this tire model in mind as a possible test subject.

Third Consideration

What about 275/60R20 (33”) tires (offered only on the Gen 2 Dual Standard vehicles)? Is a fair 20- versus and 22-inch wheel-set comparison possible using 33-inch tires exclusively?

Results:

Unfortunately, no (within the tires listed at the Riviantrackr site). There appear to be no 33-inch AS or AT tire-models that can fit both 20- and 22-inch wheel sizes.

Fourth Consideration

So far we have just one tire that (a) meets Rivian size and load-capacity requirements and (b) is available for both 20- and 22-inch wheel sizes, and it is an AT tire not necessarily meant to improve range.

What if we modify the original restrictions and consider testing different_tire models?

Results:

This certainly increases the number of possible pairings considerably, mostly because there are a number of 34-inch AS tire choices available for 20-inch Rivian wheels.

To simplify things somewhat, I suggest comparing 34-inch tires for 20-inch wheels strictly to just the OEM Pirelli (33”) tires only; specifically to the Pirelli Scorpion MS Elect tire model, since it is apparently the current factory OEM tire paired with 22-inch OEM (Sport and Range) wheels. (Also previously used by Rivian: the somewhat similar Pirelli Scorpion Zero AS Elect tire model. See photos of tread designs for the two Pirelli Scorpion tire models, below.)

Proposed Experimental (Test) Designs

Taking the results of these four considerations, what types of experiments might be performed to test the idea that 20-inch wheel and 34-inch AS tire sizes can be selected to achieve better range?

Side-note: In science, it is the role of the theoretical scientist to ponder, review, mathematically model, propose hypotheses, and inspire empirical experimentation. The more pragmatic experimental scientist takes up the challenge of evaluating hypotheses by use of actual physical experiments (with testing performed in the laboratory or in the field). (Note: This is an obvious over-simplification.)​

In this instance, I am happy to adopt the far-easier role of “theoretical scientist” and to turn over the expense and effort of experimentation to others.**​

Possible Experimental Design #1​

Hypothesis: All else being equal (held constant)***, a 275/65R20 (34”) all-terrain (AT) BF Goodrich tire should result in greater range than the same tire in the 275/50R22 (33”) size on Rivian R1 vehicles.

20" Wheel + 34" AT Tire (275/65R20)	vs.	22" Wheel + 33" AT Tire (275/50R22)
BF Goodrich All Terrain T/A KO3​	-​	BF Goodrich All Terrain T/A KO3​

BF Goodrich All
Terrain T/A KO3 tread
(Note the more aggressive,
potentially range-robbing
tread design.)


Possible Experimental Design #2​

Hypothesis: All else being equal***, a 275/65R20 (34”) all-season (AS) tire should result in greater maximum range than a 275/50R22 (33”) AS Pirelli tire on Rivian R1 vehicles.

20" Wheel + 34" AS Tires (275/65R20)	vs.	22" Wheel + 33" AS Tire (275/50R22)
Continental Terrain Contact H/T​	-​	Pirelli Scorpion MS Elect​
Goodyear Wrangler Workhorse HT​	-​	Pirelli Scorpion MS Elect​
Michelin Defender LTX Platinum​	-​	Pirelli Scorpion MS Elect​
Toyo Open Country H/T​	-​	Pirelli Scorpion MS Elect​
Yokojama Geolander H/T​	-​	Pirelli Scorpion MS Elect​
Any other 34" AS tire of interest.​	-​	Pirelli Scorpion MS Elect​

Comments

• To be more meaningful, Experimental Design #1 could be repeated a number of times. (Other vehicles, other drivers, and other test courses could be used, if desired. But of course, care should be taken to hold every variable--except wheel/tire sizes--constant within each individual [paired] experiment. An individual "experiment" would therefore consists of a pair of otherwise identical runs, once with the 34" BF Goodrich tires and once using the 33" BF Goodrich tires.)
• In Experimental Design #2 the tires listed above are arbitrarily selected. Any of the Rivian Trackr site 34" AS tire-models could be used.
• In Experimental Design #2, an actual individual experiment would also consist of a pair of otherwise matched (most variables held constant) runs, once with with 34" tires and once with the 33" (Pirelli) tires. But in this case, one other variable would differ: different tire brands would be allowed (by necessity).
• Therefore, if in Experimental Design #2 a significant difference in range were_determined between 34- and 33-inch tires, one could still not be absolutely_certain that it was not due to differences in tread/tire design.
  • In order to help diminish effects from differences in tread and tire design, conclusions reached from Experimental Design #2 might benefit from testing as many different brands of 34-inch AS tires (always versus the OEM Pirelli 33” tires) as possible. (Unfortunately, the cost and effort of such comprehensive testing would be exorbitant and unreasonable.)
  • One possible work-around would be to collect a relatively large sample of results (maybe ~30 or more?) from individual driver-vehicle tests over time. For example:
    • Driver A tests one brand of 34-inch AS tires versus the OEM Pirelli 33-inch AS tires using his Gen 2 R1T.
    • Driver B tests a different brand of 34-inch AS tires versus the OEM Pirelli 33-inch AS tires using her Gen 1 R1S. (If enough data is collected, the use of different vehicle models and generations is probably acceptable.)
    • Driver C performs a third test. And so forth...
    • Still expensive in time and money, but at least the cost would be spread around.
    • Although experimental effects due to various uncontrolled factors (in relying on multiple drivers and vehicles) could be significant, bias might be overcome and results/conclusions made more valid by using a fairly large sample size (and if care is taken by the test drivers).
• As opposed to performing such expensive, time-consuming, real-world experiments, another way to gather adequate quantities of occasionally-useful data is to review historic findings from already-reported, sometimes anecdotal, observations. So, for example, one could search the entire Rivian Forums site and collect any pertinent range data reported. However, there are potential roadblocks. There is no guarantee that sufficient quantities of acceptable data will be found. And since observer-posters were probably not thinking of future rigorous comparisons, individual reports may not provide completely valid results. Furthermore, conclusions reached from cherry-picked data can be unsound. Within reason, large sample sizes may sometimes help overcome this, and honest “trends” can occasionally still be uncovered. (Also, it helps that we are not talking about critical "rocket science" here, where lives are at stake. Still, range can cumulatively have meaningful financial and environmental implications.)
• For those (many) readers who may be understandably thinking, “Darn, this is sure a lot of time and effort to expend.” YES! Now you are getting the picture. (Despite what high-school athletes sometimes choose to believe, science is not for sissies!) Finding out how the world really works can take a lot of time and effort (and money). But it tends to generally result in the most truthful (and therefore valuable) conclusions.

_____
* One non-scientist who nonetheless seems to approach testing and information reporting in a fairly “scientific” manner is Tom Moloughney of the YouTube channel “State of Charge”. When he does evaluate range, he seems to instinctively use a good basic test design. However, to my knowledge Mr. Moloughney (who has over time developed extensive expertise and, apparently, built a lucrative career about EV charging) has not to my knowledge performed a comparison of range for Rivian (or any other) vehicles with different wheel-sets. (BTW, he does appear to get adequately compensated for his time and efforts, via sponsors I assume. Good for him.)
** Because I am pretending to be a scientist-theorist and not an experimenter, no tires were harmed in the making of this analysis.
*** Variables to be controlled (held constant) include the test vehicle, distance traveled, test ‘track’ or route, driver, average speed, weather conditions including headwind and ambient temperatures, and so forth.

Gallery of Various All-Season Tire Treads
(for tires listed in Experiment #2)​

Continental Terrain Contact H/T (for 20" wheels)​	Goodyear Wrangler Workhorse HT (20")​	Toyo Open Country H/T (20")​
Yokojama Geolander H/T (20")​	Pirelli Scorpion MS Elect (22")​	Pirelli Scorpion Zero AS Elect (22")​

Some Additional 34" Tires for 20-inch Rivian Wheels​

Bridgestone Dueler H-T 685​

Falken Wildpeak H-T02​

Firestone Transforce HT2​

Added (tire-related) Bonus:
Who Owns What?​

Here is a partial list. According to Google and United Tires:

Michelin (France) owns:	Bridgestone (Japan) owns:	Sinochem (China) owns:	Goodyear (USA) owns:	Continental (Germany) owns:
BF Goodrich Kormoran Taurus Kleber Uniroyal​	Firestone Primewell Fuzion​	Pirelli​	Cooper Mickey Thompson Avon Kelly Dunlop​	General Hoosier​

See United Tires site for tires made in the USA. (The tire industry is continually changing.)

 

[mkhuffman]

Further Thoughts on Increasing
Driving Range in R1S and R1T​

The Original Post #1 (cheekily) advocates for higher-profile, road tires on smaller (20") wheel-rims (as opposed to lower-profile tires on larger 22" wheel-rims, as Rivian seems to be doing) as a means to maximize range (as well as road comfort, tire durability, etc.).

Yet definitive proof for this (heretical) idea is lacking. Why?

Simple. It’s a big deal--expensive and time consuming--to decisively evaluate range among different wheels/tires. No individual driver--especially one not receiving adequate compensation--can reasonably be expected to expend the kind of resources necessary to ‘scientifically’ determine which wheel-sets result in the best range.*​

And unfortunately, we cannot necessary rely on the tire industry and the automotive media. Tires are consumable auto-parts that (a) are absolutely necessary, (b) often have to be replaced multiple times in the lives of most vehicles, and (c) are relatively-expensive. As a result, tire production and sales is a multi-billion-dollar, highly-competitive industry.​

As Rivian drivers know, tire prices vary wildly (and sometimes seemingly inexplicably) among brands and even among different sizes of the same tire-models. (Tires sometimes seem like commodities, with prices set or fluctuating based on supply-and-demand and what is in-fashion rather than being strictly determined just by production costs and overhead alone.) Bottom line: It can seem difficult to find truly unbiased and comparable published tire-test results.​

Suppose someone did want to attempt to accurately test the effect that Rivian wheel and tires sizes have on maximum range; what is involved?

Variables that should be held reasonably constant during testing include:

• The test vehicles--use of the same model-version, in the same condition, and preferably the exact same test vehicle.
• The driver(s)--the same driver, where possible.
• Weather--e.g., dry pavement, similar ambient temperatures and wind patterns, and so forth.
• The test 'track' or route.

And importantly (yet frequently violated):​

• The tread design (pattern, depth) and tire architecture (number/type of layers, rubber composition, wall thickness, etc.)—in other words, testers should try to use the same tire model (but in different sizes).

In an ideal test (of wheel/tire sizes on range), only wheel diameter and tire sidewall height (not the width or total tire diameter, and not the tire brand or model) would vary. (As we’ll see, this is easier said than done.)

Unfortunately, these test requirements create difficulties. When wheel/tire sizes are purposefully changed, it is usually with a different intended purpose in mind, and therefore the tread design and tire construction usually changes also (which can prejudice the outcome and invalidate resulting conclusions).

Think about it. How many Rivian drivers maintain two sets of differently-sized wheels outfitted with the same model of tires? Probably none. Most drivers who bother to maintain two or more sets of wheels of different sizes probably do so for different intended purposes (e.g., summer versus winter conditions; on-road versus off-road travel; etc.). So not only do wheel and tire sizes differ, but tread design and rubber compositions also tend to be different. Therefore, some conclusions reached after range evaluations can be legitimately questioned (for example in the case of this highly-viewed online range evaluation).​

Assuming that all this is true, how could a driver theoretically evaluate range in an unbiased manner? How about using a single tire model that (a) meets Rivian factory OEM size and load requirements and (b) is available for both the factory 20-inch and 22-inch sizes wheel sizes. (Not so easy to do, as we will see.)

For this hypothetical experimental test design, I will ignore Rivian’s (Gen 1) 21-inch wheel and (Gen 2) 33-inch (275/60R20) tire. That leaves the following wheel-sets to be compared:

• 20-inch (OEM) wheels with 34-inch (275/65R20) tires
• 22-inch (OEM) wheels with 33-inch (275/50R22) tires

These wheel-sets (a) stay within the Rivian factory OEM playing-field, (b) represent current wheel/tire sizes for most unmodified Gen 2 vehicles and, I believe, (c) provide the largest difference in sidewall height (≈profile) between two stock Rivian OEM tires. (So they stand the greatest chance of revealing a range difference if my premise is correct.)

As stated above, theoretically we would want to use the same brand and model of tire—i.e., the same tread and over-all tire design—for both wheel-sets. (It goes without saying that we would also want all tires tested to be undamaged and without repairs, be inflated to the factory-recommended pressures, and have approximately the same level of wear, if any.)

So, under these restrictions, what test tires should/could be used? Here's where things get dicey.

First Consideration

I choose to limit options to the following:

• Tires listed in the Rivian Tire Guide.
• Rivian factory OEM wheel and tire sizes.
• Tires with a Load Index of 116 or greater.
• 275/65R20 (34” diameter) versus 275/50R22 (33”) tire sizes.
• “All-Season” (AS) tires only.
• No 3PMSF (a winter-condition designation) tires.

Results:

• No one tire model is available that fits both 20-inch and 22-inch wheels.
• While there is a Michelin “Defender” tire model that fits 20-inch wheels and another one that fits 22-inch wheels, unfortunately the tread design of the two Michelin tires appears significantly different.

Michelin Defender LTX Platinum tread (275/65R20)​

Michelin Defender LTX M/S2 tread (275/50R22)​

By the way, including 3PMSF-designated tires does not seem to increase the number of potential tire candidates.

Second Consideration

As we know, Rivian R1 vehicles are relatively heavy and designed for off-road-related recreation. While such tires are not intended to provide maximum range, suppose we look at all-terrain (AT) tires in the 20- and 22-inch sizes?

Results:

The available selection includes many 20-inch tires, but almost no 22-inch equivalents, with one exception:

• The BF Goodrich All Terrain T/A KO3 (available for both 20” and 22” wheels).

Although use of an all-terrain tire may not result in maximum range, it may provide an interesting test of the effect of wheel/tire size on range. Let’s keep this tire model in mind as a possible test subject.

Third Consideration

What about 275/60R20 (33”) tires (found only on the Gen 2 Dual Standard vehicles)? Is a fair 20- versus and 22-inch comparison possible using 33-inch tires exclusively?

Results:

Unfortunately, no (within the tires listed at the Riviantrackr site). There appear to be no 33-inch AS or AT tire-models that can fit both 20- and 22-inch wheel sizes.

Fourth Consideration

So far we have just one tire that (a) meets Rivian size and load-capacity requirements and (b) is available for both 20- and 22-inch wheel sizes, and it is an AT tire not necessarily meant to improve range.

What if we modify the original restrictions and consider testing different tire models?

Results:

This certainly increases the number of possible pairings considerably, mostly because there are a number of 20-inch-wheel AS tire choices.

To simplify things somewhat, I suggest comparing tires for 20-inch wheels strictly to OEM Pirelli (33”) tires only; specifically to the Pirelli Scorpion MS Elect model, since it is apparently the current factory OEM tire paired with 22-inch OEM (Sport and Range) wheels. (Also previously used by Rivian: the somewhat similar Pirelli Scorpion Zero AS Elect tire model.)

Proposed Experimental (Test) Designs

In science, it is the role of the theoretical scientist to ponder, review, mathematically model, propose hypotheses, and inspire empirical testing. The more pragmatic experimental scientist takes up the challenge of evaluating hypotheses by use of actual physical experiments (with testing performed in the laboratory or in the field). (Note: This is an obvious over-simplification.)​

In this instance, I am happy to adopt the far-easier role of “theoretical scientist” and to turn over the expense and effort of experimentation to others.**​

Possible Experiment #1​

Hypothesis: All else being equal (held constant)***, a 275/65R20 (34”) all-terrain (AT) tire should result in greater range than a 275/50R20 (33”) AT tire on Rivian R1 vehicles.

20" Wheel + 34" AT Tire	22" Wheel + 33" AT Tire
Test Subject #1 BF Goodrich All Terrain T/A KO3 (size: 275/65R20)​	Test Subject #2 BF Goodrich All Terrain T/A KO3 (275/50R22)​

BF Goodrich All
Terrain T/A KO3 tread
(Note the more aggressive,
potentially range-robbing
tread design.)


Possible Experiment #2​

Hypothesis: All else being equal***, a 275/65R20 (34”) all-season (AS) tire should result in greater maximum range than a 275/50R20 (33”) AS tire on Rivian R1 vehicles.

20" Wheel + 34" AS Tires	22" Wheel + 33" AS Tire
Test Subject #1 Continental Terrain Contact H/T (275/65R20)​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​
Test Subject #3 Goodyear Wrangler Workhorse HT (275/65R20)​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​
Test Subject #4 Michelin Defender LTX Platinum (275/65R20)​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​
Test Subject #5 Toyo Open Country H/T (275/65R20)​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​
Test Subject #6 Yokojama Geolander H/T (275/65R20)​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​
Continue test with, or substitute, any 275/65R20 AS tire of interest.​	Test Subject #2 Pirelli Scorpion MS Elect (275/50R22)​

Gallery of Various All-Season Tire Treads
(for tires listed in Experiment #2)​

Continental Terrain Contact H/T (for 20" wheels)​	Goodyear Wrangler Workhorse HT (20")​	Toyo Open Country H/T (20")​
Yokojama Geolander H/T (20")​	Pirelli Scorpion MS Elect (22")​	Pirelli Scorpion Zero AS Elect (22")​

Notes

• To be more meaningful, Experiment #1 should probably be repeated a number of times perhaps using different drivers, vehicles, test routes, distances and so forth.
• In Experiment #2 the tires listed above are arbitrarily selected. According to the Rivian Trackr site there are about 18 AS tire-models (of the correct size and load capacity) to choose from.
• If in Experiment #2 a significant difference in range were_determined between 34- and 33-inch tires, one could still not be absolutely certain that it was not due to differences in tread/tire design alone.
  • In order to help eliminate effects from differences in tread and tire design, conclusions reached in Experiment #2 would benefit from testing as many 20-inch tires (versus the OEM Pirelli 22” tires) as possible. However, clearly the cost and effort of such comprehensive testing would be exorbitant and unreasonable.
  • One possible work-around would be to collect a relatively large sample of results (maybe ~30 or more?) from individual driver-vehicle tests over time. For example:
    • Driver A tests one brand of 34-inch tires versus the Pirelli 33-inch tires using his Gen 2 R1T.
    • Driver B tests a different brand of 34-inch tires versus the Pirelli 33-inch tires using her Gen 1 R1S. (For this test procedure, the use of different vehicle models and generations may be acceptable.)
    • Test by a Driver C,…and so forth.
    • Although experimental bias due to various uncontrolled factors could be significant, bias might be overcome and results/conclusions made valid by using a fairly large sample size (and by the good-intentioned efforts of test drivers).
• As opposed to performing brand new, expensive real-world experiments, another way to gather occasionally useful data is to review historic findings from already-reported, sometimes anecdotal, observations. So, for example, one could search the Rivian Forums site and collect all pertinent range data reported. However, since they were not intended for rigid experimental comparison, individual reports may not provide valid results, and conclusions from cherry-picked data can be unsound. Large sample sizes sometimes help overcome this, and true “trends” can nevertheless be revealed.
• For those (many) readers who may be thinking, “Darn, that is sure a lot of time and effort to expend.” YES; now you are getting the picture. Finding out how the world really works can take a lot of time and effort (and money). But it tends to generally result in the most truthful (and therefore valuable) conclusions.

_____
* One non-scientist who nevertheless seems to approach testing for range fairly “scientifically” is Tom Moloughney of the YouTube channel “State of Charge”. When he does evaluate range, he seems to instinctively use a good basic test design. However, to my knowledge Mr. Moloughney (who has over time developed extensive expertise and built a lucrative career about EV charging) (a) has not really performed a comparison of range for Rivian (or any other brand) vehicles with different wheel-sets, but (b) does happen to get very well compensated for his time and efforts (via sponsors).
** No tires were harmed in the making of this analysis.
*** Variables to be controlled (held constant) include test vehicle, distance traveled, ‘track’ or route, driver, average speed, weather conditions including headwind and ambient temperatures, and so forth.

Dude.

 

[mkhuffman]

But seriously, that post was an epic effort. And I agree: it is very hard to do the evaluation.

From my perspective, only highway range matters. And so the test must be at highway speeds. So not only do you have to do the testing in manor as you suggest, you need to decide if is an EPA test, a city test, or a highway test.

At a steady state speed, rolling resistance and aerodynamics are the primary drivers of efficiency. Weight will come into play when you have to slow down or speed up, but at a steady highway speed, we only really need to consider those two.

IMO the best approach is to put the lowest rolling resistance tire on the most areodynamic wheel. For Rivian, they did that with the 22" Range. But if you can find a low rolling resistance 20" tire in the right size and weight, one that is at least as good as the 22", and you find a aerodynamic rim, you can beat that 22" Range wheel in efficiency. But I have yet to see a combination that is convincingly better than the 22" Range.

If Hankook ever makes the iON AS SUV tire to fit the 20" Rivian rim, I am pretty sure it will be better (probably much better) than the 22" Range. Assuming the rim has decent aerodynamics. One day they might.

And if @MountainPassPerformance ever makes the areo covers for their Rivian wheels, we will have a great option for those Hankooks to go on.

Until then, it is a crap shoot and not worth the effort. IMO. Just get the 22" Range and be happy it is the best Rivian offers.

 

[DayTripping]

Keep in mind, the faster you go, the less this will matter as aerodynamic drag becomes the greatest consumer of energy by far. So for me, I haven't worried that much about tire efficiency. In Texas, I spend probably more time at higher speeds than you might in most states besides Florida and some Western states.

For the times I am spending at 40 mph, my range is going to be pretty good as well due to the lower speeds and less overall drag.

Academically it is interesting to me, practically, not so much. I went with what was seemed to be a less efficient tire and I didn't really care as I knew in my use case it wouldn't make that much of a difference and that has proven to be true. I've had 3 sets of tires on my truck (Gen 1 R1T quad); 20" factory Pirelli AT, 21" factor AS, and 21" Goodyear Territory AT (which are an option on Gen 2's and more of an aggressive AS/milder AT tire).

Now that my temps are similar to what I ran my 21" Pirellis, my 20" Goodyears (GY) are pretty much equalling or beating them in efficiency. I put on my GY in sub freezing temps and my 21's never saw those temps while I've had my truck.

If I am willing to drive between 50-60 mph on the highway, I can easily beat the highway EPA rating (for the 21" tire) for my truck with either tire set and get in the high 300's out of my large pack, whereas the factory 20" ATs exceed their claimed range but lag the others.

Most people worry about their range on the highway, not around town. If I were hyper focused on range, I'd do all I could to clean up the aerodynamic profile of the truck, more than focus on tires. Not saying tires don't matter, they matter less than aero at 70 mph. If I were going on a long trip, I'd remove any light bars, cargo racks, etc. I'd probably go to the trouble to tape all the seams between door panels. I would be running any running boards. I'd go with the most aerodynamic wheel style I could or put on areo wheel covers if I had them, run my truck in the lowest drive mode possible, and so on. Those things would likely net you more gains than what tires you are running at higher speeds. I am sure there are some incredibly inefficient AT tires that could be more impectul to range but I'd definitely focus on aero. I'd extend the little tire flaps down in front of the tires. I enclose the tires as much as I could. I smooth the seal around the windows and pano roof. There are so many places you can make improvements on this truck that incrementally would matter. Unfortunately some might impact usability but on a long trip, it might be worth it.

The way I see it, is we aren't chasing the biggest use of energy and tire drag varies mostly linearly, whereas aerodynamic drag increases exponentially.

 

[mkhuffman]

Hey, range chasers. Just wanted to highlight what I think looks like a pretty decently aerodynamic rim:
https://www.rivianforums.com/forum/...for-rivian-by-atomic-wheels.38346/post-747574

It would be better for the smooth part to be on the outside, where the rim is rotating the fastest, but still. The openings are small and look like they would not "grab" too much air. IMO they are much better than the stock 22" Darks/Brights, and with the large sidewalls on a 20" low rolling resistance tire, they should rock. In theory. The problem is finding a low rolling resistance 20" tire that can support the weight of a R1.

Keep in mind, the faster you go, the less this will matter as aerodynamic drag becomes the greatest consumer of energy by far. So for me, I haven't worried that much about tire efficiency. In Texas, I spend probably more time at higher speeds than you might in most states besides Florida and some Western states.

I agree with you, but....

Rolling resistance is very important. It impacts efficiency at all speeds. Certainly at 120 mph areodynamics are going have a massive impact, but at 80 mph so does rolling resistance. If you put a low rolling resistance tire on your vehicle, you will see an efficiency improvement at 80 mph. Definitely.

BTW - Ventilation resistance is the resistance from the wheel rotating.

 

[kanundrum]

I still need a clean run with out wind I bet it can crack 2.9+ on the highway

 

[mkhuffman]

I still need a clean run with out wind I bet it can crack 2.9+ on the highway

At what speed?

 

[kanundrum]

At what speed?

I usually do 70-75mph. 60 isn't realistic

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