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Cooper Tires
Cooper Tires COO Discoverer AT3 LT LT275/65R18/10
Cooper Tires COO Discoverer AT3 LT LT275/65R18/10
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Looking for a 275/65R18 all terrain tire? The Cooper Tires Discoverer AT3 LT is available now at ThreePiece.us with free shipping on every order and Affirm financing at checkout.
What 275/65R18 means
In the size 275/65R18, 275 is the section width in millimeters (10.83 in), 65 is the aspect ratio — the sidewall stands 65% as tall as the tire is wide, or 178.8 mm (7.04 in) — R denotes radial construction, and 18 is the wheel diameter in inches. That works out to an overall diameter of about 32.07 inches, turning roughly 629 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 123 — a maximum load of 3,417 lbs per tire. The speed symbol S corresponds to a maximum sustained speed of 112 mph.
Specifications
| Size | LT275/65R18/10 |
| Tire Type | All Terrain |
| Service Description | 123S |
| Load Index | 123 |
| Speed Rating | S |
| Load Range | SL |
| Section Width (mm) | 275 |
| Aspect Ratio | 65 |
| Overall Diameter (in) | 32.09 |
| Tread Depth (/32") | 16 |
| Warranty | 60K |
Frequently asked questions
What kind of tire is the Cooper Tires Discoverer AT3 LT?
The Cooper Tires Discoverer AT3 LT in 275/65R18 is a all terrain tire.
What warranty does the Cooper Tires Discoverer AT3 LT carry?
The manufacturer's warranty on this tire is 60K.
What does 123S mean on the Cooper Tires Discoverer AT3 LT?
123S breaks down as load index 123 — rated for 3,417 lbs per tire — with an S speed rating, good for a maximum sustained 112 mph.
Keep shopping
Shop all 275/65R18 tires, see every Cooper Tires Discoverer AT3 LT size, explore all terrain tires, or view all tires at ThreePiece.us.
- BRAND:
- Cooper Tires
- Model:
- COO Discoverer AT3 LT
- Size:
- LT275/65R18/10
- Aspect Ratio:
- 65
- Load Index:
- 123
- Load Range:
- SL
- Section Width:
- 275
- Service Description:
- 123S
- Speed Index:
- S
- Temperature:
- N/A
- Tire Rim Diameter:
- 32.09
- Tire Type:
- All Terrain
- Traction:
- N/A
- Tread Wear:
- N/A
- Tread Depth:
- 16
- UQTG:
- N/A
- Warranty:
- 60K
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