Tire Ruler285/75R18 dimensions
| Overall diameter (height) | 34.83″ · 885 mm |
| Section width | 11.22″ · 285 mm |
| Sidewall height | 8.42″ · 214 mm |
| Wheel diameter | 18″ |
| Rim width (rule of thumb) | 8–10″ |
| Circumference | 109.4″ |
| Revolutions per mile | 579 |
| In inches (flotation style) | 34.8 × 11.2R18 |
How it’s calculated: the sidewall is 75% of the 285 mm width = 213.8 mm (8.42″). Add two sidewalls to the 18″ wheel: 18 + 2 × 8.42 = 34.83″.
Bigger tires than 285/75R18 on 18″ wheels
| Size | Height | Taller by | 60 mph reads |
|---|---|---|---|
| 37x12.50R18 | 37.0″ | +2.17″ (+6.2%) | 63.7 mph |
“60 mph reads” is your real speed when a speedometer set up for 285/75R18 shows 60. Above about 3% taller, most trucks need a leveling kit or lift, and the speedometer should be recalibrated.
Sizes equivalent to 285/75R18
Within 1.5% of the same height on an 18″ wheel. Usually interchangeable for the speedometer; check width, load index and clearance.
| Size | Height | Width | Difference |
|---|---|---|---|
| 35x12.50R18 | 35.0″ | 12.5″ | +0.5% |
| 325/65R18 | 34.6″ | 12.8″ | −0.6% |
Same height on a different wheel size
Changing wheel size (plus or minus sizing) while keeping the overall height keeps your speedometer right:
- 35x12.50R15: 35.0″ tall on a 15″ wheel (+0.5%)
- 315/75R16: 34.6″ tall on a 16″ wheel (−0.7%)
- 315/70R17: 34.4″ tall on a 17″ wheel (−1.3%)
- 35x12.50R17: 35.0″ tall on a 17″ wheel (+0.5%)
- 285/65R20: 34.6″ tall on a 20″ wheel (−0.7%)
- 295/65R20: 35.1″ tall on a 20″ wheel (+0.8%)
- 35x12.50R20: 35.0″ tall on a 20″ wheel (+0.5%)
- 35x13.50R20: 35.0″ tall on a 20″ wheel (+0.5%)
- 35x12.50R22: 35.0″ tall on a 22″ wheel (+0.5%)
Popular 285/75R18 comparisons
Frequently asked questions
Is 285/75R18 a 35 inch tire?
Yes. 285/75R18 is 34.83 inches tall, so it's sold and talked about as a 35-inch tire.
What size is 285/75R18 in inches?
285/75R18 is 34.8 inches tall (overall diameter), 11.2 inches wide, with a 8.4 inch sidewall, and fits an 18 inch wheel.
What tire size is equivalent to 285/75R18?
Sizes within 1.5% of the same diameter on an 18" wheel: 35x12.50R18 (35.0"), 325/65R18 (34.6"). Check load index and width before swapping.
What rim width fits 285/75R18?
As a rule of thumb, about 8–10 inches. The tire maker's spec sheet lists the approved range for each model.
How many revolutions per mile does 285/75R18 make?
About 579 revolutions per mile in theory (circumference 109.4 in). Real tires turn slightly more because they flatten under load.