Write a Review
Cooper Tires
Cooper Tires COO Discoverer AT3 LT LT245/75R17/10
Cooper Tires COO Discoverer AT3 LT LT245/75R17/10
📧 Get Fitment Help
Verify parts fit & get product recommendations
Lease-to-own for as low as
/week
Get Started
Guaranteed to Fit — confirm your size with the fitment checker on this page
Price Match Guarantee Learn More
Free Mount & Balance
Free Shipping
OUT OF STOCK 
📧 Get Fitment Help
Verify parts fit & get product recommendations
The Cooper Tires Discoverer AT3 LT in 245/75R17 ships free from ThreePiece.us, with Affirm financing available at checkout and fast delivery from a nationwide warehouse network.
What 245/75R17 means
In the size 245/75R17, 245 is the section width in millimeters (9.65 in), 75 is the aspect ratio — the sidewall stands 75% as tall as the tire is wide, or 183.8 mm (7.23 in) — R denotes radial construction, and 17 is the wheel diameter in inches. That works out to an overall diameter of about 31.47 inches, turning roughly 641 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 121 — a maximum load of 3,197 lbs per tire. The speed symbol S corresponds to a maximum sustained speed of 112 mph.
Specifications
| Size | LT245/75R17/10 |
| Tire Type | All Terrain |
| Service Description | 121S |
| Load Index | 121 |
| Speed Rating | S |
| Load Range | SL |
| Section Width (mm) | 245 |
| Aspect Ratio | 75 |
| Overall Diameter (in) | 31.5 |
| Tread Depth (/32") | 16 |
| Warranty | 60K |
Frequently asked questions
What does 121S mean on the Cooper Tires Discoverer AT3 LT?
121S breaks down as load index 121 — rated for 3,197 lbs per tire — with an S speed rating, good for a maximum sustained 112 mph.
What kind of tire is the Cooper Tires Discoverer AT3 LT?
The Cooper Tires Discoverer AT3 LT in 245/75R17 is a all terrain tire.
What warranty does the Cooper Tires Discoverer AT3 LT carry?
The manufacturer's warranty on this tire is 60K.
Keep shopping
Shop all 245/75R17 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:
- LT245/75R17/10
- Aspect Ratio:
- 75
- Load Index:
- 121
- Load Range:
- SL
- Section Width:
- 245
- Service Description:
- 121S
- Speed Index:
- S
- Temperature:
- N/A
- Tire Rim Diameter:
- 31.5
- Tire Type:
- All Terrain
- Traction:
- N/A
- Tread Wear:
- N/A
- Tread Depth:
- 16
- UQTG:
- N/A
- Warranty:
- 60K
PRODUCT REVIEWS (0)
Overall Rankings
Have you tried this product?
WRITE A REVIEWNo reviews for this product yet. Be the first to write a review!
Write a Review