Cooper AT3 vs Toyo AT3 for a Tacoma or Midsize Truck
Short answer
Two all-terrains that share a name, not a profile. The Toyo Open Country A/T III blends 8.1 to the Cooper Discoverer AT3's 7.6 and wins six axes, trail by 2. The Cooper wins value and efficiency, sits a budget tier lower, and lists 6 factory Tacoma sizes to the Toyo's 2. Upsizing favours the Toyo; replacing stock favours the Cooper.
Cooper AT3 vs Toyo AT3: same badge, different jobs
"AT3" means two unrelated tires. Cooper's Discoverer AT3 family and Toyo's Open Country A/T III come from different companies; they both carry the severe-snow mark, and both turn up on Tacomas and other midsize pickups shopping for a do-everything tread. Our dataset scores the Cooper as one row, the Discoverer AT3 4S/LT, against the Toyo's single Open Country A/T III row. Both rows sit in the all-terrain category, so they are judged inside the same field of 18 all-terrains.
| Score axis (0-10) | Cooper Discoverer AT3 4S/LT | Toyo Open Country A/T III | Edge |
|---|---|---|---|
| Road comfort | 8 | 8 | Tie |
| Wet grip | 8 | 8 | Tie |
| Snow | 8 | 9 | Toyo by 1 |
| Trail | 6 | 8 | Toyo by 2 |
| Mud (not blended) | 4 | 5 | Toyo by 1 |
| Durability | 7 | 8 | Toyo by 1 |
| Tread life | 8 | 9 | Toyo by 1 |
| Efficiency (not blended) | 7 | 6 | Cooper by 1 |
| Looks (not blended) | 5 | 7 | Toyo by 2 |
| Value | 8 | 7 | Cooper by 1 |
| Blended score (7 axes) | 7.6 | 8.1 | Toyo by 0.5 |
How far these numbers go
The axes are an editorial synthesis, not a test: the research set reads 83 cited documents, and 3 of them stand behind the Cooper row and 3 behind the Toyo row. Taco Tires measured no wear, noise, or stopping distance on either. Read a one- or two-point gap as an editorial lean, never as a lab margin.
Where the Toyo Open Country A/T III wins
Six axes. Trail is the big one at 8 against 6, and looks match that 2-point gap at 7 against 5, though looks sit outside the blend. Snow, mud, durability, and tread life each go to the Toyo by one point: 9-8, 5-4, 8-7, and 9-8. Four of those six count toward the blend, which is how the Toyo opens a 0.5-point lead even after losing value.
- Trail 8 vs 6: the dataset tags the Cooper for moderate trail use and the Toyo for daily driving plus trail. If the truck sees rutted fire roads or rocky two-track, this is the axis to weight.
- Snow 9 vs 8: both are 3PMSF rated in the dataset (confirm the symbol on your exact size); the Toyo holds the highest snow mark any tire in the set earns and the Cooper sits one step below it.
- Tread life 9 vs 8: the Toyo's listed strengths include tread life, and the score agrees.
Where the Cooper Discoverer AT3 wins
Value is 8 against 7 and efficiency is 7 against 6. Value is in the blend and efficiency is not, so only one of these shows in the headline figure. The budget tiers back the value point: the dataset puts the Cooper in its mid tier and the Toyo in its high tier. We do not publish prices, so get quotes in your exact size before treating the tier as a dollar figure.
Road comfort and wet grip tie at 8 and 8, so the Cooper gives up nothing on the pavement axes most daily drivers feel. For a Tacoma that rarely leaves the road, the Cooper's profile reads as the better buy: equal on-road scores, a lighter-rolling tread by our efficiency mark, and a lower tier.
The Cooper is the less aggressive-looking tire
Looks is 5 against 7, and the dataset lists "most aggressive look" among the Cooper's reasons to pass. If the tire is meant to fill a lifted Tacoma's wheel well visually, that matters; if it is going on a stock truck, it probably does not.
Rank and blended score, kept apart
| Measure | Cooper Discoverer AT3 4S/LT | Toyo Open Country A/T III |
|---|---|---|
| Editorial rank, all models | #11 of 50 | #4 of 50 |
| Place inside its category | 7th of 18 all-terrains | 3rd of 18 all-terrains |
| Blended score (0-10) | 7.6 | 8.1 |
In this pair the two measures agree: the Toyo is #4 of 50 and 3rd among all-terrains, the Cooper #11 and 7th, and the Toyo also blends higher. That agreement is not automatic. The General Grabber A/TX, the Hankook Dynapro AT2 Xtreme, the Continental TerrainContact A/T2, and the Falken Rubitrek A/T all blend to the same 7.6 as the Cooper while ranking anywhere from #12 to #44. The Sumitomo Encounter AT2 (#43, blended 7.7) outscores the Cooper on the blend from a lower rank. Rank is the research set's editorial ordering, not a sort on the blended score, so quote whichever one answers your question and do not swap them.
Tacoma sizes: replacement vs upsize
This is where the two catalogs really part. Only 4 sizes appear on both rows: 265/75R16, 265/70R17, 275/70R17, and 285/70R17. The Cooper adds 6 sizes the Toyo row lacks, topping out at 275/65R18, while the Toyo adds 7 the Cooper lacks, reaching 295/70R18 at about 34.3 inches.
- Cooper sizes that match a factory Tacoma size in our 3rd- and 4th-gen fitment data: 245/75R16 (3rd gen Tacoma), 265/70R16 (3rd gen Tacoma), 265/65R17 (3rd gen Tacoma), 245/70R17 (4th gen Tacoma), 265/70R17 (4th gen Tacoma), and 265/65R18 (4th gen Tacoma).
- Toyo sizes that match one: 265/70R17 (4th gen Tacoma) and 265/70R18 (4th gen Tacoma).
- Toyo-only sizes: 285/75R16, 255/80R17, 285/75R17, 265/70R18, 275/70R18, 285/70R18, and 295/70R18, running from about 32.6 to 34.3 inches tall.
- 265/75R16
- 265/70R17
- 275/70R17
- 285/70R17
- 245/75R16
- 265/70R16
- 265/65R17
- 245/70R17
- 265/65R18
- 285/75R16
- 255/80R17
- 285/75R17
- 265/70R18
- 275/70R18
- 285/70R18
Listed is not the same as cleared
The lists record which sizes each model is offered in, not whether a size clears your truck. Each size page carries the conservative clearance verdict by generation; check it, and match or exceed the factory load index, before you order.
Which AT3 should go on your Tacoma?
- Pick the Toyo Open Country A/T III if the truck sees real dirt or you are moving up a size: trail 8 vs 6, blended 8.1, and the deeper catalog of tall sizes.
- Pick the Cooper Discoverer AT3 if you are replacing a factory size on a mostly-pavement truck: equal comfort and wet grip, value 8 and efficiency 7, a lower budget tier, and more factory sizes on its list.
- Do not pick on winter alone: both are 3PMSF rated, one point apart on our snow axis.
Frequently asked questions
On blended score the Toyo Open Country A/T III leads, 8.1 to 7.6, and it wins trail, snow, mud, durability, tread life, and looks. The Cooper Discoverer AT3 wins value and efficiency and ties on comfort and wet grip. For a Tacoma or other midsize pickup that stays mostly on pavement in a stock size, the Cooper is the sensible buy; for one that goes off-road or up a size, the Toyo is.
The Toyo, by one step: tread life 9 against 8. That is an editorial reading of the cited manufacturer pages, write-ups, and owner reports, not a wear test. The Cooper's better efficiency (7 vs 6) and lower budget tier partly offset that over the life of a set.
Yes. 265/70R17 is one of the 4 sizes both rows list, along with 265/75R16, 275/70R17, and 285/70R17. Outside those, the Cooper covers more of the smaller factory sizes and the Toyo covers the taller upsizes.
Keep going
Sources
- TrailTacoma: 3rd-gen all-terrain owner setups
- TrailTacoma: H/T, A/T, R/T and M/T tradeoffs for Tacoma owners
- Cooper Discoverer AT3 XLT product page (coopertire.com) - the Cooper manufacturer page the dataset cites for its AT3 4S/LT row
- Tacoma4G: 4th-gen tire choice discussion
- Toyo Open Country A/T III product page (toyotires.com)
- 3 cited documents sit behind the Discoverer AT3 row and 3 behind the Open Country A/T III row; the ten axes are a synthesis of those, not a Taco Tires test
Compare your exact sizes
Run any size in this guide through the Tacoma tire size calculator to see diameter, width, speedometer error, effective gearing, and highway RPM before you buy.