205/50R16 vs 215/40R17
Switching from 205/50R16 to 215/40R17 decreases the overall diameter by 7.6 mm (1.2%). That is within the usual ±3% guideline.
| 205/50R16 | 215/40R17 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 205 mm | 215 mm | +10.0 |
| Sidewall height | 102.5 mm | 86.0 mm | -16.5 |
| Rim diameter | 406.4 mm | 431.8 mm | +25.4 |
| Overall diameter | 611.4 mm | 603.8 mm | -7.6 |
| Circumference | 1,920.8 mm | 1,896.9 mm | -23.9 |
| Revolutions | 521 per km | 527 per km | +6.0 |
Speedometer effect
With 215/40R17 fitted on a car calibrated for 205/50R16, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 49.4 km/h |
| 80 km/h | 79.0 km/h |
| 100 km/h | 98.8 km/h |
| 120 km/h | 118.5 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 215 mm tire has a manufacturer-specified rim width range.
205/50R16 dimensions · 215/40R17 dimensions · Open in calculator