285/45R21 tire size
A 285/45R21 tire is 31.10 inches (789.9 mm) tall, 11.22 in (285 mm) wide and fits a 21-inch wheel. In inch notation it is roughly a 31.1x11.2R21 — a "31-inch" tire.
| Overall diameter | 31.10 in | 789.9 mm |
|---|---|---|
| Section width | 11.22 in | 285 mm |
| Sidewall height | 5.05 in | 128.3 mm |
| Circumference | 97.70 in | 2,482 mm |
| Revolutions | 648.5 per mile | 403.0 per km |
| Rim diameter | 21 in | 533.4 mm |
Compare 285/45R21 with another size
Alternative sizes on the same 21-inch wheel
Sizes in use within ±3 % of the overall diameter of 285/45R21:
Plus and minus sizes for 285/45R21
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 255/60R19 | Minus 2 (19 in) | 31.05 in | −0.16% |
| 275/55R19 | Minus 2 (19 in) | 30.91 in | −0.61% |
| 265/55R19 | Minus 2 (19 in) | 30.48 in | −2.00% |
| 255/55R20 | Minus 1 (20 in) | 31.04 in | −0.18% |
| 285/50R20 | Minus 1 (20 in) | 31.22 in | +0.39% |
| 275/50R20 | Minus 1 (20 in) | 30.83 in | −0.87% |
| 295/45R20 | Minus 1 (20 in) | 30.45 in | −2.08% |
| 255/45R22 | Plus 1 (22 in) | 31.04 in | −0.20% |
| 285/40R22 | Plus 1 (22 in) | 30.98 in | −0.39% |
| 325/35R22 | Plus 1 (22 in) | 30.96 in | −0.46% |
| 295/40R22 | Plus 1 (22 in) | 31.29 in | +0.62% |
| 295/35R23 | Plus 2 (23 in) | 31.13 in | +0.10% |
| 255/40R23 | Plus 2 (23 in) | 31.03 in | −0.22% |
| 285/35R23 | Plus 2 (23 in) | 30.85 in | −0.78% |
| 305/35R23 | Plus 2 (23 in) | 31.41 in | +0.99% |
Vehicles approved with 285/45R21 tires
Models whose Swiss type approval lists 285/45R21 as a standard or optional size (973 approvals in total). Always check your own vehicle's placard or papers.
- Audi Q8
- BMW X7
- Bentley Bentayga
- Lamborghini 636
- Rolls-Royce Phantom
- BMW XM
- Audi SQ8
- Kia EV9
- Mercedes-Benz G-Class
- Porsche Cayenne
- Mercedes-Benz GLE
- Rolls-Royce Cullinan
- Alpina XB7
- Hyundai Ioniq
- Aston Martin DBX
Source: Swiss Federal Roads Office (FEDRO/ASTRA), open government data. Original data (downloaded 2026-09-29). Data processed by us; errors in processing are ours, not the publisher's.
Nearby 21-inch sizes
Reading the 285/45R21 size
- 285 — section width in millimetres (11.22 in).
- 45 — aspect ratio: the sidewall is 45 % of the width, 128.3 mm.
- R — radial construction (ZR on the sidewall means a high-speed rated radial; the dimensions are the same).
- 21 — fits a 21-inch diameter wheel.
The load index and speed rating (for example 91V) follow the size on the sidewall. They must meet at least the values on your vehicle's tire placard.