Write a Review
Cooper
Cooper Discoverer STT Pro LT285/70R17/10 121/118Q - 170114034
Cooper Discoverer STT Pro LT285/70R17/10 121/118Q - 170114034
📧 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
Shop the Cooper Discoverer STT Pro 285/70R17 at ThreePiece.us — free shipping on every order, Affirm financing available, and fast delivery nationwide.
What 285/70R17 means
In the size 285/70R17, 285 is the section width in millimeters (11.22 in), 70 is the aspect ratio — the sidewall stands 70% as tall as the tire is wide, or 199.5 mm (7.85 in) — R denotes radial construction, and 17 is the wheel diameter in inches. That works out to an overall diameter of about 32.71 inches, turning roughly 617 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 manufacturer lists the overall diameter of this specific tire as 33.03 inches — when clearance is tight, go by the published figure rather than the nominal size math.
The service description on this tire decodes to a load index of 121 — a maximum load of 3,197 lbs per tire, or 118 (2,910 lbs) per tire when mounted as duals. The speed symbol Q corresponds to a maximum sustained speed of 99 mph.
Specifications
| Size | LT285/70R17/10 |
| Tire Type | All Season |
| Service Description | 121/118Q |
| Load Index | 121/118 |
| Speed Rating | Q |
| Load Range | 10 |
| Section Width (mm) | 285 |
| Aspect Ratio | 70 |
| Overall Diameter (in) | 33.03 |
| Tread Depth (/32") | 19 |
Frequently asked questions
Will 285/70R17 tires fit my vehicle?
Check the size molded into your current tire's sidewall or the tire placard inside the driver's door jamb — if it reads 285/70R17, this tire matches your vehicle's fitment. If you're changing sizes, compare overall diameter to keep your speedometer and clearances right. See every 285/70R17 tire in stock to compare options.
What does 121/118Q mean on the Cooper Discoverer STT Pro?
121/118Q breaks down as load index 121 — rated for 3,197 lbs per tire (118, or 2,910 lbs, in dual fitment) — with a Q speed rating, good for a maximum sustained 99 mph.
What kind of tire is the Cooper Discoverer STT Pro?
The Cooper Discoverer STT Pro in 285/70R17 is a all season tire.
Keep shopping
Shop all 285/70R17 tires, browse Cooper tires, see every Cooper Discoverer STT Pro size, or view all tires at ThreePiece.us.
- BRAND:
- Cooper
- Model:
- Discoverer STT Pro
- Size:
- LT285/70R17/10
- Aspect Ratio:
- 70
- Load Index:
- 121/118
- Load Range:
- 10
- Section Width:
- 285
- Service Description:
- 121/118Q
- Speed Index:
- Q
- Tire Rim Diameter:
- 33.03
- Tire Type:
- All Season
- Tread Depth:
- 19
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