245/45R21 tire size
A 245/45R21 tire is 29.68 inches (753.9 mm) tall, 9.65 in (245 mm) wide and fits a 21-inch wheel. In inch notation it is roughly a 29.7x9.6R21 — a "30-inch" tire.
| Overall diameter | 29.68 in | 753.9 mm |
|---|---|---|
| Section width | 9.65 in | 245 mm |
| Sidewall height | 4.34 in | 110.3 mm |
| Circumference | 93.25 in | 2,368 mm |
| Revolutions | 679.5 per mile | 422.2 per km |
| Rim diameter | 21 in | 533.4 mm |
Compare 245/45R21 with another size
Alternative sizes on the same 21-inch wheel
Sizes in use within ±3 % of the overall diameter of 245/45R21:
Plus and minus sizes for 245/45R21
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 275/50R19 | Minus 2 (19 in) | 29.83 in | +0.49% |
| 295/45R19 | Minus 2 (19 in) | 29.45 in | −0.77% |
| 265/50R19 | Minus 2 (19 in) | 29.43 in | −0.84% |
| 255/55R19 | Minus 2 (19 in) | 30.04 in | +1.22% |
| 245/50R20 | Minus 1 (20 in) | 29.65 in | −0.12% |
| 275/45R20 | Minus 1 (20 in) | 29.74 in | +0.21% |
| 265/45R20 | Minus 1 (20 in) | 29.39 in | −0.98% |
| 255/50R20 | Minus 1 (20 in) | 30.04 in | +1.21% |
| 275/35R22 | Plus 1 (22 in) | 29.58 in | −0.34% |
| 285/35R22 | Plus 1 (22 in) | 29.85 in | +0.58% |
| 255/40R22 | Plus 1 (22 in) | 30.03 in | +1.18% |
| 265/35R22 | Plus 1 (22 in) | 29.30 in | −1.27% |
Vehicles approved with 245/45R21 tires
Models whose Swiss type approval lists 245/45R21 as a standard or optional size (168 approvals in total). Always check your own vehicle's placard or papers.
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 245/45R21 size
- 245 — section width in millimetres (9.65 in).
- 45 — aspect ratio: the sidewall is 45 % of the width, 110.3 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.