235/55R19 vs 245/60R18
Switching from 235/55R19 to 245/60R18 increases the overall diameter by 10.1 mm (1.4%). That is within the usual ±3% guideline.
| 235/55R19 | 245/60R18 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 235 mm | 245 mm | +10.0 |
| Sidewall height | 129.2 mm | 147.0 mm | +17.8 |
| Rim diameter | 482.6 mm | 457.2 mm | -25.4 |
| Overall diameter | 741.1 mm | 751.2 mm | +10.1 |
| Circumference | 2,328.2 mm | 2,360.0 mm | +31.8 |
| Revolutions | 430 per km | 424 per km | -6.0 |
Speedometer effect
With 245/60R18 fitted on a car calibrated for 235/55R19, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 50.7 km/h |
| 80 km/h | 81.1 km/h |
| 100 km/h | 101.4 km/h |
| 120 km/h | 121.6 km/h |
Larger tires make the car go faster than the speedometer shows. Most speedometers also read slightly high from the factory.
Before you change size
- Check the sizes approved for your vehicle on the door-jamb placard or in the owner's manual.
- Check clearance to suspension, brakes and arches at full lock and full compression.
- Match or exceed the original load index and speed rating.
- Wider tires need an appropriate rim width; a 245 mm tire has a manufacturer-specified rim width range.
235/55R19 dimensions · 245/60R18 dimensions · Open in calculator