225/70R16 vs 235/60R17
Switching from 225/70R16 to 235/60R17 decreases the overall diameter by 7.6 mm (1.1%). That is within the usual ±3% guideline.
| 225/70R16 | 235/60R17 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 225 mm | 235 mm | +10.0 |
| Sidewall height | 157.5 mm | 141.0 mm | -16.5 |
| Rim diameter | 406.4 mm | 431.8 mm | +25.4 |
| Overall diameter | 721.4 mm | 713.8 mm | -7.6 |
| Circumference | 2,266.3 mm | 2,242.5 mm | -23.8 |
| Revolutions | 441 per km | 446 per km | +5.0 |
Speedometer effect
With 235/60R17 fitted on a car calibrated for 225/70R16, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 49.5 km/h |
| 80 km/h | 79.2 km/h |
| 100 km/h | 98.9 km/h |
| 120 km/h | 118.7 km/h |
Smaller tires make the speedometer read higher than the actual speed. 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 235 mm tire has a manufacturer-specified rim width range.
225/70R16 dimensions · 235/60R17 dimensions · Open in calculator