275/30R21 tire size
A 275/30R21 tire is 27.50 inches (698.4 mm) tall, 10.83 in (275 mm) wide and fits a 21-inch wheel. In inch notation it is roughly a 27.5x10.8R21.
| Overall diameter | 27.50 in | 698.4 mm |
|---|---|---|
| Section width | 10.83 in | 275 mm |
| Sidewall height | 3.25 in | 82.5 mm |
| Circumference | 86.38 in | 2,194 mm |
| Revolutions | 733.5 per mile | 455.8 per km |
| Rim diameter | 21 in | 533.4 mm |
Compare 275/30R21 with another size
Alternative sizes on the same 21-inch wheel
Sizes in use within ±3 % of the overall diameter of 275/30R21:
Plus and minus sizes for 275/30R21
| Size | Wheel | Diameter | Difference |
|---|---|---|---|
| 305/35R19 | Minus 2 (19 in) | 27.41 in | −0.33% |
| 265/40R19 | Minus 2 (19 in) | 27.35 in | −0.54% |
| 275/40R19 | Minus 2 (19 in) | 27.66 in | +0.60% |
| 245/45R19 | Minus 2 (19 in) | 27.68 in | +0.67% |
| 315/30R20 | Minus 1 (20 in) | 27.44 in | −0.20% |
| 275/35R20 | Minus 1 (20 in) | 27.58 in | +0.30% |
| 325/30R20 | Minus 1 (20 in) | 27.68 in | +0.66% |
| 265/35R20 | Minus 1 (20 in) | 27.30 in | −0.70% |
Vehicles approved with 275/30R21 tires
Models whose Swiss type approval lists 275/30R21 as a standard or optional size (1,020 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 275/30R21 size
- 275 — section width in millimetres (10.83 in).
- 30 — aspect ratio: the sidewall is 30 % of the width, 82.5 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.