185/60R15 vs 205/50R16

Switching from 185/60R15 to 205/50R16 increases the overall diameter by 8.4 mm (1.4%). That is within the usual ±3% guideline.

185/60R15205/50R16Difference (mm / revs)
Section width185 mm205 mm+20.0
Sidewall height111.0 mm102.5 mm-8.5
Rim diameter381.0 mm406.4 mm+25.4
Overall diameter603.0 mm611.4 mm+8.4
Circumference1,894.4 mm1,920.8 mm+26.4
Revolutions528 per km521 per km-7.0

Speedometer effect

With 205/50R16 fitted on a car calibrated for 185/60R15, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.7 km/h
80 km/h81.1 km/h
100 km/h101.4 km/h
120 km/h121.7 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

185/60R15 dimensions · 205/50R16 dimensions · Open in calculator