245/45R18 tire size
A 245/45R18 tire is 245 mm wide with a sidewall 45% of its width (110.2 mm), fits a 18-inch rim and has an overall diameter of 678 mm (26.7 in).
| Dimension | Metric | Imperial |
|---|---|---|
| Section width | 245 mm | 9.65 in |
| Sidewall height | 110.2 mm | 4.34 in |
| Rim diameter | 457.2 mm | 18 in |
| Overall diameter | 677.7 mm | 26.68 in |
| Circumference | 2,129.1 mm | 83.82 in |
| Revolutions | 470 per km | 756 per mile |
Reading the size 245/45R18
245Width in mm45Aspect ratio (sidewall % of width)RRadial construction18Rim diameter in inches
The load index and speed rating (for example 91V) follow the size on the sidewall. Replacement tires should match or exceed the original load index and speed rating.
Alternative sizes within 3% of 245/45R18
A replacement size should stay within about 3% of the original diameter so the speedometer, ABS and transmission stay accurate. Always check clearance, load index and the vehicle manufacturer's approved sizes.
| Size | Diameter | Difference | Speedo reads 100 → actual | |
|---|---|---|---|---|
| 245/40R19 | 679 mm | +0.1% | 100.1 | Compare |
| 225/60R16 | 676 mm | -0.2% | 99.8 | Compare |
| 225/55R17 | 679 mm | +0.2% | 100.2 | Compare |
| 245/35R20 | 680 mm | +0.3% | 100.3 | Compare |
| 215/70R15 | 682 mm | +0.6% | 100.6 | Compare |
| 225/50R18 | 682 mm | +0.7% | 100.7 | Compare |
| 205/65R16 | 673 mm | -0.7% | 99.3 | Compare |
| 235/40R19 | 671 mm | -1.0% | 99.0 | Compare |
Compare 245/45R18 with any size →