185/65R15 vs 195/70R14

Switching from 185/65R15 to 195/70R14 increases the overall diameter by 7.1 mm (1.1%). That is within the usual ±3% guideline.

185/65R15195/70R14Difference (mm / revs)
Section width185 mm195 mm+10.0
Sidewall height120.2 mm136.5 mm+16.3
Rim diameter381.0 mm355.6 mm-25.4
Overall diameter621.5 mm628.6 mm+7.1
Circumference1,952.5 mm1,974.8 mm+22.3
Revolutions512 per km506 per km-6.0

Speedometer effect

With 195/70R14 fitted on a car calibrated for 185/65R15, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.6 km/h
80 km/h80.9 km/h
100 km/h101.1 km/h
120 km/h121.4 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

185/65R15 dimensions · 195/70R14 dimensions · Open in calculator