Toyo Open Country A/T III: Four Tires, Same Name, Only One Is Right for Your Truck

The Name Game That Costs You Money

You walk into a tire shop and say "I want Toyo Open Country AT3s in 275/65R20." The guy nods, types something into the computer, and orders your tires. Two weeks later you're in the bay, they mount them up, and you drive home feeling great.

Except he ordered the wrong ones. And you won't know for thousands of miles -- or until you're on a trail doing math in your head and realizing the numbers don't add up.

This happens more than it should. Because Toyo makes four tires that all share nearly the same name, in nearly the same size, on the same shelf in the catalog. They are not the same tire. Two of them aren't even the same physical size. And one of them might not pass the federal load safety standard on your truck.

Here's every variant, what makes each one different, and which one you actually want.

The Full Lineup: Side by Side

All four tires share the Toyo Open Country A/T III name. That's where the similarities end.

Read that table slowly. There are traps in it.

The Trap Nobody Warns You About

The Non-EV SL Is a Different Size

This is the big one. Three of those four tires are 275/65R20 -- 34.1 inches in overall diameter. The non-EV SL is 275/60R20 -- a 60-series aspect ratio instead of 65. That drops the overall diameter to 33 inches. One full inch shorter.

If a tire shop looks up "Toyo Open Country AT3, 275, R20" and grabs the cheapest SL option, they might hand you the 275/60R20. You'd get tires that are physically smaller than what your vehicle was designed for -- a shorter sidewall, less air volume, less ground clearance, and a speedometer that reads wrong.

On a vehicle that came with 275/65R20 tires, a 275/60R20 is the wrong size. It's not a close-enough situation. It's a different tire on a different fitment.

Load Index 115 Doesn't Pass the Math on Heavy Trucks

The non-EV SL carries a Load Index of 115 -- max load of 2,679 lbs per tire. That's 77 lbs less than the EV SL's Load Index 116 (2,756 lbs).

For a lot of vehicles, 77 lbs doesn't matter. But if you drive something heavy -- a Rivian, a Ford Lightning, a loaded half-ton -- it matters a lot.

Here's why. Federal safety standards (FMVSS 110) require that passenger-type tires (both P-metric and Euro-metric, which includes both SL variants here) get de-rated by a factor of 1.1 when installed on trucks, SUVs, and multi-purpose vehicles. That de-rating math on the non-EV SL:

• Rear GAWR (Rivian example): 4,960 lbs
• Per rear tire: 4,960 / 2 = 2,480 lbs
• Non-EV SL max load (LI 115): 2,679 lbs
• After FMVSS de-rating (/ 1.1): 2,435 lbs
• Deficit: 45 lbs per tire

That's not a margin. That's a miss. The tire doesn't meet the federal standard for the rear axle. And that's at full rated pressure -- before you air down a single PSI.

For the full breakdown of why this math matters and how the de-rating rule works, see the Rivian tire guide and the SL vs LT deep dive.

Breaking Down Each Variant

1. Open Country A/T III EV -- SL (275/65R20, LI 116)

The lightweight EV-optimized all-terrain.

This is Toyo's answer to the question "what if I want an all-terrain on my Rivian but I don't want to lose a ton of range?" Low rolling resistance technology keeps efficiency closer to OEM tires. At 45 lbs, it's 10 lbs lighter per corner than the LT version. The H speed rating (130 mph) is the highest of the four -- not that you'll use it off-road, but it tells you this tire is designed for highway-biased duty.

The UTQG rating of 600 A A is strong -- 600 treadwear, A traction, A temperature. That traction grade is the only "A A" in the lineup (the non-EV SL gets A B).

The trade-off: 13.5/32" of tread depth versus 16.4/32" on the LT versions. That's nearly 3/32" less rubber between you and whatever you're driving over. And as an SL tire, the sidewall construction is thinner -- fewer plies, less puncture resistance, less structural shape at low PSI.

Best for: EV owners who want better off-road capability than stock tires without paying the full weight and range penalty of an LT swap. Highway-dominant driving with occasional dirt roads and light trails.

2. Open Country A/T III EV -- LT (LT275/65R20, LI 126/123)

The full-capability EV all-terrain.

Same low rolling resistance technology as the EV SL, but in a 10-ply E-rated LT construction. Max load jumps from 2,756 to 3,750 lbs per tire. No FMVSS de-rating because LT tires are exempt. Tread depth goes from 13.5/32" to 16.4/32" -- nearly three more thirty-seconds of rubber.

At 55 lbs, it's 10 lbs heavier per corner than the EV SL. Across four tires, that's 40 lbs of additional rotating mass. On an EV, figure 3-5% range reduction depending on conditions and driving style.

The "EV" designation means Toyo optimized the rolling resistance and noise characteristics for electric drivetrains. Whether that optimization is worth $43 more per tire than the non-EV LT depends on how much you care about squeezing back a few miles of range.

Best for: EV and heavy truck owners who do regular off-road driving and want the load capacity and sidewall strength of LT construction with the efficiency nod of EV-tuned engineering. This is the tire for Rivian and Lightning owners who take trails seriously.

3. Open Country A/T III -- LT (LT275/65R20, LI 126/123)

The standard workhorse LT.

Same exact load specs as the EV LT. Same weight (55 lbs). Same tread depth (16.4/32"). Same 10-ply E-rated construction. Same speed rating. Same max PSI.

The difference: no low rolling resistance technology. No EV-tuned anything. And it costs $434 per tire instead of $478 -- a $43 savings per tire, $172 across a set of four.

If you drive a gas or diesel truck, this is the version you want. The EV optimizations don't do anything useful on an ICE drivetrain. You're paying for range efficiency tech that only matters on electric vehicles.

If you drive an EV -- the $43 question is real. The EV LT's rolling resistance advantage might recover 1-2% range. Over the life of the tire, that's hundreds of miles of driving. Whether that's worth $172 depends on your charging situation and how range-sensitive your driving is.

Best for: Gas and diesel trucks that need a capable all-terrain in 275/65R20 LT. Also a solid budget choice for EV owners who'd rather save $172 and live with marginally higher rolling resistance.

4. Open Country A/T III -- SL (275/60R20, LI 115)

The odd one out.

This is the tire that causes the confusion. It's the cheapest of the four at $365, it's the lightest at 42 lbs, and it's the one a tire shop is most likely to grab if they're sorting by price.

It is also a different size. 275/60R20 -- not 275/65R20. That 60-series aspect ratio means a shorter sidewall and an overall diameter of 33 inches instead of 34.1. If your vehicle shipped with 275/65R20 tires, this is the wrong fitment.

It also carries the lowest Load Index of the four (115 vs 116 for the EV SL), the lowest max PSI (44 vs 51), and the lowest max load (2,679 vs 2,756). Those differences are small in isolation but they compound -- especially on heavy vehicles where the de-rating math is already tight.

The UTQG is 600 A B -- the "B" temperature rating is a step below the EV SL's "A." Both are fine for real-world driving, but it's another data point confirming this is a less capable tire.

Best for: Vehicles that actually run 275/60R20 from the factory -- like certain configurations of the Ford F-150. Not a substitute for 275/65R20 on any vehicle, regardless of what the parts counter says.

The Two LTs Are (Almost) the Same Tire

This needs to be said plainly because it confuses people: the EV LT and the standard LT are the same load rating, same weight, same tread depth, same dimensions, same speed rating. The EV version adds low rolling resistance technology and an "Electric Vehicle Tuned" designation. That's it. No structural differences. No additional load capacity.

If you're choosing between these two on a gas truck, save the $43 per tire and buy the standard LT. If you're choosing between them on an EV, the EV LT is worth considering -- but don't let anyone tell you it's a fundamentally different tire. It's the same tire with a compound optimization for efficiency.

The EV SL vs EV LT: The Real Decision for EV Owners

For most EV owners shopping these tires, the choice comes down to the EV SL (SL, 45 lbs) versus the EV LT (E-rated, 55 lbs). Here's the honest comparison:

The EV SL is the compromise tire -- lighter, quieter, more range-friendly, but with thinner sidewalls and the de-rating penalty on heavy trucks. The EV LT is the capability tire -- heavier, stiffer, louder, but with massively more load capacity and sidewall protection.

If you do light off-road (gravel, fire roads, easy dirt) and value range: the EV SL is a meaningful upgrade over OEM tires without the LT weight penalty.

If you do real trail work (rocks, ruts, recovery scenarios) or you carry heavy loads: the EV LT is the correct tool. The 10 lbs per corner is the price of admission for 50% more load capacity and 3/32" more tread between your tire and the rocks.

Speed Ratings: Why They're Different

The speed ratings across these four tires tell a story about intended use:

The EV SL gets the highest speed rating because it's the most highway-oriented tire in the lineup. The non-EV SL gets T -- still highway-capable but a step below. Both LTs get S, which is standard for E-rated LT all-terrains. Nobody is doing 130 mph off-road, so this is really about highway stability and heat management at sustained high speeds.

For practical purposes, all four tires are fine at any legal highway speed. The speed rating matters more as a proxy for the tire's intended use case than as a safety limit.

UTQG: Why the LTs Don't Have Ratings

You'll notice the two SL tires have UTQG ratings (600 A A and 600 A B) while the LTs show "N/A." This isn't because Toyo forgot to test them. LT tires are exempt from UTQG requirements. The UTQG (Uniform Tire Quality Grading) system only applies to passenger-type tires. LT-metric tires are classified differently and aren't required to carry treadwear, traction, or temperature grades.

This means you can't use UTQG to compare an SL to an LT. You can compare the two SLs to each other (the EV SL's A temperature grade beats the non-EV SL's B), but that's it.

How to Make Sure You Got the Right One

You've done the research. You've picked your variant. You placed the order. The tires arrive at the shop. Before they mount a single tire, check the sidewall yourself. Here's exactly what to look for:

If you ordered the EV SL:

• Sidewall reads: 275/65R20 116H
• No "LT" prefix
• Look for: Low Rolling Resistance marking, EV designation
• Max load on sidewall: 2,756 lbs
• Weight should be approximately 45 lbs

If you ordered the EV LT:

• Sidewall reads: LT275/65R20 126/123S
• "LT" prefix is present
• Load Range: E
• Look for: Low Rolling Resistance marking, EV designation
• Max load on sidewall: 3,750 lbs (single) / 3,415 lbs (dual)

If you ordered the standard LT:

• Sidewall reads: LT275/65R20 126/123S
• "LT" prefix is present
• Load Range: E
• No EV or Low Rolling Resistance markings
• Max load on sidewall: 3,750 lbs (single) / 3,415 lbs (dual)

If you see 275/60R20 on the sidewall -- stop. That's the non-EV SL and it's the wrong size if your vehicle runs 275/65R20. Don't let them mount it. Don't accept "it's close enough." It's a different tire.

The critical things to verify: the size designation (65 vs 60 aspect ratio), the LT prefix (or lack thereof), and the load index (115, 116, or 126/123). Those three numbers tell you exactly which of the four tires you're holding.

Which One Do You Actually Want?

You drive a Rivian, Lightning, or other heavy EV and you go off-road:

Get the AT III EV LT (LT275/65R20 126/123S). The load capacity and sidewall strength are worth the weight and cost premium. The low rolling resistance tech helps offset some of the range penalty from going LT.

You drive a Rivian or EV and you mostly stay on pavement with occasional dirt:

The AT III EV SL (275/65R20 116H) is a strong choice. Better off-road capability than OEM tires, lighter than LT, and the rolling resistance optimization keeps range impact minimal. Just understand the load capacity limits before you air down aggressively.

You drive a gas or diesel truck and you want a solid LT all-terrain:

Get the AT III LT (LT275/65R20 126/123S). Same tire as the EV version for $43 less per tire. The low rolling resistance tech doesn't benefit your drivetrain. Save the money.

Your vehicle runs 275/60R20 from the factory:

The AT III SL (275/60R20 115T) is your tire. But only if that's actually your factory size. Don't buy this for a vehicle that runs 275/65R20.

You're not sure:

Read your current tire's sidewall. Match the size exactly. Then decide SL vs LT based on your vehicle weight and off-road plans. The SL vs LT guide walks through the full decision framework.

The Bottom Line

Toyo makes an excellent all-terrain tire. They also make four versions of it with names so similar that a distracted parts counter employee can hand you the wrong one without either of you noticing until it's too late.

The fix is simple: know which variant you need before you walk into the shop. Check the sidewall before they mount. And if anyone tries to tell you the 275/60R20 is "basically the same" as the 275/65R20 -- it's not. It's an inch shorter, it carries less load, and on a heavy truck, it doesn't pass the federal safety math.

Four tires. One name. Only one is right for your truck. Now you know which one.

Air Down Smarter

Once you've got the right Toyos mounted, a MORRflate AirHub lets you air down all four tires simultaneously to a matched pressure. No walking circles around the truck with a gauge. Pair it with the MORRflate TenSix compressor for airing back up, and your trailhead routine drops to a few minutes.