Tire Ruler275/55R20 dimensions
| Overall diameter (height) | 31.91″ · 810 mm |
| Section width | 10.83″ · 275 mm |
| Sidewall height | 5.95″ · 151 mm |
| Wheel diameter | 20″ |
| Rim width (rule of thumb) | 7.5–9.5″ |
| Circumference | 100.2″ |
| Revolutions per mile | 632 |
| In inches (flotation style) | 31.9 × 10.8R20 |
How it’s calculated: the sidewall is 55% of the 275 mm width = 151.3 mm (5.95″). Add two sidewalls to the 20″ wheel: 20 + 2 × 5.95 = 31.91″.
Bigger tires than 275/55R20 on 20″ wheels
| Size | Height | Taller by | 60 mph reads |
|---|---|---|---|
| 285/55R20 | 32.3″ | +0.43″ (+1.4%) | 60.8 mph |
| 265/60R20 | 32.5″ | +0.61″ (+1.9%) | 61.1 mph |
| 295/55R20 | 32.8″ | +0.87″ (+2.7%) | 61.6 mph |
| 275/60R20 | 33.0″ | +1.08″ (+3.4%) | 62.0 mph |
| 33x12.50R20 | 33.0″ | +1.09″ (+3.4%) | 62.1 mph |
“60 mph reads” is your real speed when a speedometer set up for 275/55R20 shows 60. Above about 3% taller, most trucks need a leveling kit or lift, and the speedometer should be recalibrated.
Sizes equivalent to 275/55R20
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 |
|---|---|---|---|
| 305/50R20 | 32.0″ | 12.0″ | +0.3% |
| 245/60R20 | 31.6″ | 9.6″ | −1.0% |
| 285/55R20 | 32.3″ | 11.2″ | +1.4% |
Same height on a different wheel size
Changing wheel size (plus or minus sizing) while keeping the overall height keeps your speedometer right:
- 32x11.50R15: 32.0″ tall on a 15″ wheel (+0.3%)
- 265/75R16: 31.6″ tall on a 16″ wheel (−0.8%)
- 235/85R16: 31.7″ tall on a 16″ wheel (−0.6%)
- 265/70R17: 31.6″ tall on a 17″ wheel (−1.0%)
- 275/70R17: 32.2″ tall on a 17″ wheel (+0.8%)
- 255/75R17: 32.1″ tall on a 17″ wheel (+0.5%)
- 245/75R17: 31.5″ tall on a 17″ wheel (−1.4%)
- 275/65R18: 32.1″ tall on an 18″ wheel (+0.5%)
- 265/65R18: 31.6″ tall on an 18″ wheel (−1.1%)
- 255/70R18: 32.1″ tall on an 18″ wheel (+0.5%)
- 285/45R22: 32.1″ tall on a 22″ wheel (+0.6%)
- 275/45R22: 31.7″ tall on a 22″ wheel (−0.5%)
Popular 275/55R20 comparisons
Frequently asked questions
Is 275/55R20 a 32 inch tire?
Yes. 275/55R20 is 31.91 inches tall, so it's sold and talked about as a 32-inch tire.
What size is 275/55R20 in inches?
275/55R20 is 31.9 inches tall (overall diameter), 10.8 inches wide, with a 6.0 inch sidewall, and fits a 20 inch wheel.
What tire size is equivalent to 275/55R20?
Sizes within 1.5% of the same diameter on a 20" wheel: 305/50R20 (32.0"), 245/60R20 (31.6"), 285/55R20 (32.3"). Check load index and width before swapping.
What rim width fits 275/55R20?
As a rule of thumb, about 7.5–9.5 inches. The tire maker's spec sheet lists the approved range for each model.
How many revolutions per mile does 275/55R20 make?
About 632 revolutions per mile in theory (circumference 100.2 in). Real tires turn slightly more because they flatten under load.