Tire Ruler285/65R18 dimensions
| Overall diameter (height) | 32.59″ · 828 mm |
| Section width | 11.22″ · 285 mm |
| Sidewall height | 7.29″ · 185 mm |
| Wheel diameter | 18″ |
| Rim width (rule of thumb) | 8–10″ |
| Circumference | 102.4″ |
| Revolutions per mile | 619 |
| In inches (flotation style) | 32.6 × 11.2R18 |
How it’s calculated: the sidewall is 65% of the 285 mm width = 185.3 mm (7.29″). Add two sidewalls to the 18″ wheel: 18 + 2 × 7.29 = 32.59″.
Bigger tires than 285/65R18 on 18″ wheels
| Size | Height | Taller by | 60 mph reads |
|---|---|---|---|
| 33x12.50R18 | 33.0″ | +0.41″ (+1.3%) | 60.8 mph |
| 275/70R18 | 33.2″ | +0.57″ (+1.8%) | 61.1 mph |
| 295/70R18 | 34.3″ | +1.67″ (+5.1%) | 63.1 mph |
| 325/65R18 | 34.6″ | +2.05″ (+6.3%) | 63.8 mph |
| 285/75R18 | 34.8″ | +2.24″ (+6.9%) | 64.1 mph |
“60 mph reads” is your real speed when a speedometer set up for 285/65R18 shows 60. Above about 3% taller, most trucks need a leveling kit or lift, and the speedometer should be recalibrated.
Sizes equivalent to 285/65R18
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 |
|---|---|---|---|
| 265/70R18 | 32.6″ | 10.4″ | +0.1% |
| 33x12.50R18 | 33.0″ | 12.5″ | +1.3% |
Same height on a different wheel size
Changing wheel size (plus or minus sizing) while keeping the overall height keeps your speedometer right:
- 33x12.50R15: 33.0″ tall on a 15″ wheel (+1.3%)
- 285/75R16: 32.8″ tall on a 16″ wheel (+0.7%)
- 285/70R17: 32.7″ tall on a 17″ wheel (+0.4%)
- 275/70R17: 32.2″ tall on a 17″ wheel (−1.3%)
- 255/80R17: 33.1″ tall on a 17″ wheel (+1.5%)
- 33x12.50R17: 33.0″ tall on a 17″ wheel (+1.3%)
- 275/60R20: 33.0″ tall on a 20″ wheel (+1.2%)
- 285/55R20: 32.3″ tall on a 20″ wheel (−0.7%)
- 295/55R20: 32.8″ tall on a 20″ wheel (+0.6%)
- 265/60R20: 32.5″ tall on a 20″ wheel (−0.2%)
- 33x12.50R20: 33.0″ tall on a 20″ wheel (+1.3%)
- 285/45R22: 32.1″ tall on a 22″ wheel (−1.5%)
- 305/45R22: 32.8″ tall on a 22″ wheel (+0.7%)
- 275/50R22: 32.8″ tall on a 22″ wheel (+0.7%)
- 33x12.50R22: 33.0″ tall on a 22″ wheel (+1.3%)
Popular 285/65R18 comparisons
Frequently asked questions
Is 285/65R18 a 33 inch tire?
Not quite. 285/65R18 is 32.59 inches tall, between a 32 and a 33 inch tire.
What size is 285/65R18 in inches?
285/65R18 is 32.6 inches tall (overall diameter), 11.2 inches wide, with a 7.3 inch sidewall, and fits an 18 inch wheel.
What tire size is equivalent to 285/65R18?
Sizes within 1.5% of the same diameter on an 18" wheel: 265/70R18 (32.6"), 33x12.50R18 (33.0"). Check load index and width before swapping.
What rim width fits 285/65R18?
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 285/65R18 make?
About 619 revolutions per mile in theory (circumference 102.4 in). Real tires turn slightly more because they flatten under load.