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Dunlop Grandtrek AT20 vs Cooper Discoverer STT PRO — Compared

Relative Score (0–100): 60% professional tests, 40% owner reviews.

Discoverer STT PRO is ahead, 63–46

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Category by category

Relative Score per category, 0–100. Open “Why this score” for the tests and owner ratings behind it.

  1. 43

    Dry

    Discoverer STT PRO +22
    65
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online2963
  2. 43

    Wet

    Discoverer STT PRO +24
    67
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online3366
  3. 49

    Snow

    Discoverer STT PRO +17
    66
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online3664
  4. 52

    Comfort

    Discoverer STT PRO +9
    61
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online3452
  5. 57

    Noise

    Grandtrek AT20 +4
    53
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online4234
  6. 52

    Treadwear

    Discoverer STT PRO +11
    63
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online4262
  7. 34

    Handling

    Discoverer STT PRO +20
    54
    Why this score
    SourceGrandtrek AT20Discoverer STT PRO
    Reviews found online3454
Scores at a glance
CategoryDunlop Grandtrek AT20Cooper Discoverer STT PRO
Relative Score 46 63
Dry 43 65
Wet 43 67
Snow 49 66
Comfort 52 61
Noise 57 53
Treadwear 52 63
Handling 34 54

Higher is better. The Relative Score follows your weights below; category scores do not change.

Weight the categories that matter to you

Wet grip and treadwear start at “Important” — the two things buyers rank highest. Move the sliders and the scores update instantly.

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Recomputed
Headline score

Grandtrek AT20

Discoverer STT PRO

Pros, cons & observations

Themes extracted from owner reviews found online — not the opinion of TireWheelGuide.

Tire A Grandtrek AT20

Pros

  • Exceptional tread life and high mileage capability (often exceeding 40,000 to 60,000+ miles)
  • Comfortable, smooth, and quiet ride on tarmac and highways
  • Good stability and predictable handling in dry, warm weather conditions

Cons

  • Extremely poor and potentially unsafe traction on wet roads, leading to sliding and long braking distances
  • Unreliable or hazardous performance in winter conditions like snow and ice
  • Subpar off-road capabilities, including low puncture resistance on gravel and poor traction in mud or sand
All owner themes in the Grandtrek AT20 review

Tire B Discoverer STT PRO

Pros

  • Outstanding off-road traction in mud, rocks, and dirt
  • Surprisingly low road noise and smooth ride for a mud-terrain tire
  • Aggressive and appealing visual design with tough sidewalls

Cons

  • Can be difficult to balance properly, leading to vibrations for some users
  • Faster tread wear reported by a subset of drivers under heavy use
  • Reduced traction in specific conditions like deep sand or packed snow/ice
All owner themes in the Discoverer STT PRO review

Specs side by side

Attribute A · Dunlop Grandtrek AT20 B · Cooper Discoverer STT PRO
CategoryAll SeasonAll Season
Vehicle typeSUV and 4x4SUV and 4x4
Sizes available923
Rim diameters15″ – 18″16″ – 20″
Tread depth—18 - 22/32″
SidewallBlackwallBlack Side Wall - Raised White Lettering
Max pressure—35 - 80 psi

Which one should you actually buy?

Dunlop Grandtrek AT20

Cooper Discoverer STT PRO

Winner: Cooper Discoverer STT PRO — better wet, dry and handling. Pick the Dunlop Grandtrek AT20 if noise matters most to you.

Pick tire B Your priority is wet-weather safety

Cooper Discoverer STT PRO scores 67 vs 43 on wet.

Pick tire B You want the most grip on dry roads

Cooper Discoverer STT PRO scores 65 vs 43 on dry.

Pick tire B You enjoy sharp, responsive handling

Cooper Discoverer STT PRO scores 54 vs 34 on handling.

Pick tire B You drive through snowy winters

Cooper Discoverer STT PRO scores 66 vs 49 on snow.

Tire A · Dunlop Grandtrek AT20
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Tire B · Cooper Discoverer STT PRO
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How do we compare tires?

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.

63

Leads

Discoverer STT PRO

Amazon