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Cooper Tires
Cooper Tires COO Discoverer AT3 4S 255/50R20XL
Cooper Tires COO Discoverer AT3 4S 255/50R20XL
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Shop the Cooper Tires Discoverer AT3 4S 255/50R20 at ThreePiece.us — free shipping on every order, Affirm financing available, and fast delivery nationwide.
What 255/50R20 means
In the size 255/50R20, 255 is the section width in millimeters (10.04 in), 50 is the aspect ratio — the sidewall stands 50% as tall as the tire is wide, or 127.5 mm (5.02 in) — R denotes radial construction, and 20 is the wheel diameter in inches. That works out to an overall diameter of about 30.04 inches, turning roughly 671 revolutions per mile. Overall diameter is what matters for speedometer accuracy and clearance when you change sizes, so compare it — not just the width — against your current tire.
The service description on this tire decodes to a load index of 109 — a maximum load of 2,271 lbs per tire. The speed symbol H corresponds to a maximum sustained speed of 130 mph.
Specifications
| Size | 255/50R20XL |
| Tire Type | All Terrain |
| Service Description | 109H |
| Load Index | 109 |
| Speed Rating | H |
| Load Range | XL |
| Section Width (mm) | 255 |
| Aspect Ratio | 50 |
| Overall Diameter (in) | 30.08 |
| Tread Depth (/32") | 12 |
| Treadwear | 620 |
| Traction Grade | A |
| Temperature Grade | B |
| UTQG | 620AB |
| Warranty | 65K |
Frequently asked questions
What are the treadwear and warranty ratings on the Cooper Tires Discoverer AT3 4S?
This tire carries a treadwear grade of 620, traction grade A, temperature grade B under UTQG. The manufacturer's warranty is 65K.
What does 109H mean on the Cooper Tires Discoverer AT3 4S?
109H breaks down as load index 109 — rated for 2,271 lbs per tire — with an H speed rating, good for a maximum sustained 130 mph.
What kind of tire is the Cooper Tires Discoverer AT3 4S?
The Cooper Tires Discoverer AT3 4S in 255/50R20 is a all terrain tire.
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Shop all 255/50R20 tires, see every Cooper Tires Discoverer AT3 4S size, explore all terrain tires, or view all tires at ThreePiece.us.
- BRAND:
- Cooper Tires
- Model:
- COO Discoverer AT3 4S
- Size:
- 255/50R20XL
- Aspect Ratio:
- 50
- Load Index:
- 109
- Load Range:
- XL
- Section Width:
- 255
- Service Description:
- 109H
- Speed Index:
- H
- Temperature:
- B
- Tire Rim Diameter:
- 30.08
- Tire Type:
- All Terrain
- Traction:
- A
- Tread Wear:
- 620
- Tread Depth:
- 12
- UQTG:
- 620AB
- Warranty:
- 65K
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