275/55R20 Tire Size in Inches — Diameter, Width & Specs
A 275/55R20 tire is 31.91 inches tall (overall diameter), 10.83 inches wide, with a 5.95-inch sidewall, on a 20-inch wheel. In millimeters: 811 × 275.
275/55R20 drawn to scale — diameter, sidewall and rim from the size code.
Full specifications
| Measurement | Inches | Millimeters |
|---|---|---|
| Overall diameter | 31.91 in | 811 mm |
| Tire width | 10.83 in | 275 mm |
| Sidewall height | 5.95 in | 151 mm |
| Circumference | 100.2 in | 2546 mm |
| Revolutions per mile (nominal) | 632 | |
| Wheel (rim) diameter | 20 in | 508 mm |
Same-diameter alternatives (20" rim)
| Size | Diameter | Width | Diameter difference |
|---|---|---|---|
| 285/55R20 | 32.34" | 11.22" | 1.36% |
Popular comparisons with the 275/55R20
Load index & speed rating — how to read them
The size code is only half of the sidewall. After it comes a load index and a speed letter, like 121R. Load index 121 means one tire carries up to 3,197 lbs at its rated pressure; speed rating R means up to 106 mph. A replacement tire must meet or exceed both numbers on your vehicle's door-jamb placard. Calculate another size or compare two sizes.
How tall is a 275/55R20 tire?
31.91 inches overall diameter (811 mm), from the standard size formula. A specific brand's measured height can differ by a few tenths.
How wide is a 275/55R20?
10.83 inches (275 mm) at the casing's widest point, unloaded.
What does 275/55R20 convert to in flotation (inch) sizes?
Its diameter is 31.91", so the nearest flotation class is 32-inch tires (e.g. 32x12.50R20 where that size exists). Use the converter for exact near-matches.
Nominal geometry — method. Last verified November 12, 2026.