155/80R13 vs 195/50R15
Switching from 155/80R13 to 195/50R15 decreases the overall diameter by 2.2 mm (0.4%). That is within the usual ±3% guideline.
| 155/80R13 | 195/50R15 | Difference (mm / revs) | |
|---|---|---|---|
| Section width | 155 mm | 195 mm | +40.0 |
| Sidewall height | 124.0 mm | 97.5 mm | -26.5 |
| Rim diameter | 330.2 mm | 381.0 mm | +50.8 |
| Overall diameter | 578.2 mm | 576.0 mm | -2.2 |
| Circumference | 1,816.5 mm | 1,809.6 mm | -6.9 |
| Revolutions | 551 per km | 553 per km | +2.0 |
Speedometer effect
With 195/50R15 fitted on a car calibrated for 155/80R13, the real speed when the speedometer shows:
| Speedometer shows | Actual speed |
|---|---|
| 50 km/h | 49.8 km/h |
| 80 km/h | 79.7 km/h |
| 100 km/h | 99.6 km/h |
| 120 km/h | 119.5 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 195 mm tire has a manufacturer-specified rim width range.
155/80R13 dimensions · 195/50R15 dimensions · Open in calculator