Relative Score (0–100): 60% professional tests, 40% owner reviews.
Discoverer AT3 4S is ahead, 76–46
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Tests – · 1 test Owners 81 · 688 reviews
“Suggestions for replacing AT tires on SUV I have an expedition, and used to need AT tires because of where I used to live and work, but now find I don't need them. I was running some Cooper Discoverer AT3 4S. Absolutely fantastic tires, but now I want to get some all weather since its mostly suburban and highway driving. We get a lot of snow so that's important to me as well. Any suggestions or real world advice? Thanks!”
Tests – · none yet Owners 35 · 57 reviews
Relative Score per category, 0–100. Open “Why this score” for the tests and owner ratings behind it.
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 84 | 29 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 86 | 33 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 74 | 36 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 83 | 34 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 81 | 42 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Professional tests (TWG score) | 71 | – |
| Reviews found online | 77 | 42 |
| Source | Discoverer AT3 4S | Grandtrek AT20 |
|---|---|---|
| Reviews found online | 77 | 34 |
| Category | Cooper Discoverer AT3 4S | Dunlop Grandtrek AT20 |
|---|---|---|
| Relative Score | 76 | 46 |
| Dry | 78 | 43 |
| Wet | 82 | 42 |
| Snow | 72 | 49 |
| Comfort | 76 | 51 |
| Noise | 72 | 57 |
| Treadwear | 73 | 52 |
| Handling | 77 | 34 |
Higher is better. The Relative Score follows your weights below; category scores do not change.
Wet grip and treadwear start at “Important” — the two things buyers rank highest. Move the sliders and the scores update instantly.
Discoverer AT3 4S
Grandtrek AT20
Themes extracted from owner reviews found online — not the opinion of TireWheelGuide.
From Reddit, forums and review threads. Not part of our score
Community sentiment for the Cooper Discoverer AT3 4S is predominantly positive, with drivers praising its quiet highway ride, strong traction across snow, rain, and dry pavement, and appealing appearance. Several owners note that while it handles light off-road duties and daily driving well, tread life occasionally falls short of mileage expectations. In addition, multiple posts highlight frustration and concern regarding availability and recent discontinuation across various sizes.
“Got some 225/75/16 Cooper Discoverer AT3 4s - Great fit on stock setup.”
“They Discontinued My Tire! I've been using Cooper Discoverer AT3 4s forever. For some reason Cooper, in it's infinite wisdom, has discontinued the 265 75r 16 size so I need a replacment. I'm in Southern California and do quite a bit of wildlife habitat restoration work in dry desert conditions. This involves lots and lots of highway miles as well as dirt roads from good to, on what planet is this a road. Occasionally we are even driving up dry washes, trying to avoid all the nasty sidewall eating rocks and spiny bushes. The tread on the discoverer is pretty modest and quite on the highway but when aired downed, runs well in sandy conditions. They even work pretty well in rocky conditions. The other thing is they wear really well. Ive got 60k+ miles on my current set and can squeeze another 10k out of them if I have to. So to the point, Im looking for suggestions for a replacment. Any help would be greatly appreciated.”
“I ran a set of Cooper Discoverer AT3's over 72k miles and never had an issue. loved them. now i have a set of Cooper Discoverer AT3 4S's and they are even better in traction and ride.”
Based on 27 community posts
We haven't collected enough community discussion about this tire yet.
| Attribute | A · Cooper Discoverer AT3 4S | B · Dunlop Grandtrek AT20 |
|---|---|---|
| Category | All Season | All Season |
| Vehicle type | SUV and 4x4 | SUV and 4x4 |
| Sizes available | 14 | 9 |
| Rim diameters | 15″ – 22″ | 15″ – 18″ |
| Tread depth | 12 - 14/32″ | — |
| UTQG | 620 A B | — |
| Treadwear warranty | 65,000 mi | — |
| Sidewall | Black Side Wall - Raised Outline White Lettering | Blackwall |
| Max pressure | 44 - 50 psi | — |
Cooper Discoverer AT3 4S
Dunlop Grandtrek AT20
Winner: Cooper Discoverer AT3 4S — better handling, wet and dry. It leads or ties in every category we score.
Cooper Discoverer AT3 4S scores 77 vs 34 on handling.
Cooper Discoverer AT3 4S scores 82 vs 42 on wet.
Cooper Discoverer AT3 4S scores 78 vs 43 on dry.
Cooper Discoverer AT3 4S scores 76 vs 51 on comfort.
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Every category score blends two independent signals. 60% comes from professional tire tests (braking distances, lap times, noise measurements), each result compared with every other tire in the same test and newer tests counting more. 40% comes from owner reviews found online, adjusted for how generously each site rates. Both use one scale: the average tested tire gets 70, the best 100. When a tire has only one of the two, the missing half is estimated from the other and the score stays closer to average; with no road test and fewer than five owner reviews it gets no score yet.
Community buzz from Reddit and forums is shown for context only — it never changes the score.
