175/70R13 vs 195/50R15

Switching from 175/70R13 to 195/50R15 increases the overall diameter by 0.8 mm (0.1%). That is within the usual ±3% guideline.

175/70R13195/50R15Difference (mm / revs)
Section width175 mm195 mm+20.0
Sidewall height122.5 mm97.5 mm-25.0
Rim diameter330.2 mm381.0 mm+50.8
Overall diameter575.2 mm576.0 mm+0.8
Circumference1,807.0 mm1,809.6 mm+2.6
Revolutions553 per km553 per km+0.0

Speedometer effect

With 195/50R15 fitted on a car calibrated for 175/70R13, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.1 km/h
80 km/h80.1 km/h
100 km/h100.1 km/h
120 km/h120.2 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

175/70R13 dimensions · 195/50R15 dimensions · Open in calculator