275/65R18 vs 285/75R16
Switching from 275/65R18 to 285/75R16 increases the overall diameter by 19.2 mm (2.4%). That is within the usual ±3% guideline.
| 275/65R18 | 285/75R16 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 275 mm | 285 mm | +10.0 |
| Sidewall height | 178.8 mm | 213.8 mm | +35.0 |
| Rim diameter | 457.2 mm | 406.4 mm | -50.8 |
| Overall diameter | 814.7 mm | 833.9 mm | +19.2 |
| Circumference | 2,559.5 mm | 2,619.8 mm | +60.3 |
| Revolutions | 391 per km | 382 per km | -9.0 |
Speedometer effect
With 285/75R16 fitted on a car calibrated for 275/65R18, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 51.2 km/h |
| 80 km/h | 81.9 km/h |
| 100 km/h | 102.4 km/h |
| 120 km/h | 122.8 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 285 mm tire has a manufacturer-specified rim width range.
275/65R18 dimensions · 285/75R16 dimensions · Open in calculator