305/40R22 Tyre Size — Dimensions & Alternatives
Full dimensions for 305/40R22 tires. Common on full-size luxury SUVs and trucks.
305/40R22 dimensions
| Section width | 305mm |
| Aspect ratio | 40% |
| Sidewall height | 122mm (4.80in) |
| Rim diameter | 22" (558.8mm) |
| Overall diameter | 803mm (31.61in) |
| Circumference | 2523mm |
| Revs per km | 396 |
What does 305/40R22 mean?
The tyre designation 305/40R22 breaks down into three parts: the section width (305mm — how wide the tread is), the aspect ratio (40% — sidewall height as a percentage of width), and the rim diameter (22 inches). The "R" indicates radial construction, which is standard on nearly every passenger vehicle today.
Can I fit an alternative size?
Yes — tyres with a slightly different section width, aspect ratio or rim size can often be fitted safely provided the overall diameter stays within about 3% of the original. Going wider improves grip but increases rolling resistance; going narrower reduces road noise and fuel consumption. The lookup tool below shows compatible alternative sizes for 305/40R22.
Speedometer error
Changing tyre size affects your speedometer reading. A larger overall diameter means the speedometer under-reads (you're actually going faster than the needle shows); a smaller diameter means it over-reads. Stay within 3% to keep the error under the legal tolerance in Australia and New Zealand.
