185/65R15 vs 205/60R15
Switching from 185/65R15 to 205/60R15 increases the overall diameter by 5.5 mm (0.9%). That is within the usual ±3% guideline.
| 185/65R15 | 205/60R15 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 185 mm | 205 mm | +20.0 |
| Sidewall height | 120.2 mm | 123.0 mm | +2.8 |
| Rim diameter | 381.0 mm | 381.0 mm | +0.0 |
| Overall diameter | 621.5 mm | 627.0 mm | +5.5 |
| Circumference | 1,952.5 mm | 1,969.8 mm | +17.3 |
| Revolutions | 512 per km | 508 per km | -4.0 |
Speedometer effect
With 205/60R15 fitted on a car calibrated for 185/65R15, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 50.4 km/h |
| 80 km/h | 80.7 km/h |
| 100 km/h | 100.9 km/h |
| 120 km/h | 121.1 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 205 mm tire has a manufacturer-specified rim width range.
185/65R15 dimensions · 205/60R15 dimensions · Open in calculator