165/65R14 vs 195/50R15

Switching from 165/65R14 to 195/50R15 increases the overall diameter by 5.9 mm (1.0%). That is within the usual ±3% guideline.

165/65R14195/50R15Difference (mm / revs)
Section width165 mm195 mm+30.0
Sidewall height107.2 mm97.5 mm-9.7
Rim diameter355.6 mm381.0 mm+25.4
Overall diameter570.1 mm576.0 mm+5.9
Circumference1,791.0 mm1,809.6 mm+18.6
Revolutions558 per km553 per km-5.0

Speedometer effect

With 195/50R15 fitted on a car calibrated for 165/65R14, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.5 km/h
80 km/h80.8 km/h
100 km/h101.0 km/h
120 km/h121.2 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

165/65R14 dimensions · 195/50R15 dimensions · Open in calculator