Tire Ruler285/65R20 dimensions
| Overall diameter (height) | 34.59″ · 879 mm |
| Section width | 11.22″ · 285 mm |
| Sidewall height | 7.29″ · 185 mm |
| Wheel diameter | 20″ |
| Rim width (rule of thumb) | 8–10″ |
| Circumference | 108.7″ |
| Revolutions per mile | 583 |
| In inches (flotation style) | 34.6 × 11.2R20 |
How it’s calculated: the sidewall is 65% of the 285 mm width = 185.3 mm (7.29″). Add two sidewalls to the 20″ wheel: 20 + 2 × 7.29 = 34.59″.
Bigger tires than 285/65R20 on 20″ wheels
| Size | Height | Taller by | 60 mph reads |
|---|---|---|---|
| 35x12.50R20 | 35.0″ | +0.41″ (+1.2%) | 60.7 mph |
| 35x13.50R20 | 35.0″ | +0.41″ (+1.2%) | 60.7 mph |
| 295/65R20 | 35.1″ | +0.51″ (+1.5%) | 60.9 mph |
| 325/60R20 | 35.4″ | +0.77″ (+2.2%) | 61.3 mph |
| 37x12.50R20 | 37.0″ | +2.41″ (+7.0%) | 64.2 mph |
“60 mph reads” is your real speed when a speedometer set up for 285/65R20 shows 60. Above about 3% taller, most trucks need a leveling kit or lift, and the speedometer should be recalibrated.
Sizes equivalent to 285/65R20
Within 1.5% of the same height on a 20″ wheel. Usually interchangeable for the speedometer; check width, load index and clearance.
| Size | Height | Width | Difference |
|---|---|---|---|
| 35x12.50R20 | 35.0″ | 12.5″ | +1.2% |
| 35x13.50R20 | 35.0″ | 13.5″ | +1.2% |
| 295/65R20 | 35.1″ | 11.6″ | +1.5% |
| 275/65R20 | 34.1″ | 10.8″ | −1.5% |
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 (+1.2%)
- 315/75R16: 34.6″ tall on a 16″ wheel (+0.0%)
- 315/70R17: 34.4″ tall on a 17″ wheel (−0.6%)
- 35x12.50R17: 35.0″ tall on a 17″ wheel (+1.2%)
- 295/70R18: 34.3″ tall on an 18″ wheel (−0.9%)
- 285/75R18: 34.8″ tall on an 18″ wheel (+0.7%)
- 325/65R18: 34.6″ tall on an 18″ wheel (+0.1%)
- 35x12.50R18: 35.0″ tall on an 18″ wheel (+1.2%)
- 35x12.50R22: 35.0″ tall on a 22″ wheel (+1.2%)
Popular 285/65R20 comparisons
Frequently asked questions
Is 285/65R20 a 35 inch tire?
Not quite. 285/65R20 is 34.59 inches tall, between a 34 and a 35 inch tire.
What size is 285/65R20 in inches?
285/65R20 is 34.6 inches tall (overall diameter), 11.2 inches wide, with a 7.3 inch sidewall, and fits a 20 inch wheel.
What tire size is equivalent to 285/65R20?
Sizes within 1.5% of the same diameter on a 20" wheel: 35x12.50R20 (35.0"), 35x13.50R20 (35.0"), 295/65R20 (35.1"), 275/65R20 (34.1"). Check load index and width before swapping.
What rim width fits 285/65R20?
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 285/65R20 make?
About 583 revolutions per mile in theory (circumference 108.7 in). Real tires turn slightly more because they flatten under load.