205/45R17 Tyre Size — Dimensions & Alternatives
Full dimensions for 205/45R17 tires. Find compatible alternatives and check speedometer error.
205/45R17 dimensions
| Section width | 205mm |
| Aspect ratio | 45% |
| Sidewall height | 92mm (3.62in) |
| Rim diameter | 17" (431.8mm) |
| Overall diameter | 616mm (24.25in) |
| Circumference | 1935mm |
| Revs per km | 517 |
What does 205/45R17 mean?
The tyre designation 205/45R17 breaks down into three parts: the section width (205mm — how wide the tread is), the aspect ratio (45% — sidewall height as a percentage of width), and the rim diameter (17 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 205/45R17.
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.
