195/65R15 vs 205/55R16

Switching from 195/65R15 to 205/55R16 decreases the overall diameter by 2.6 mm (0.4%). That is within the usual ±3% guideline.

195/65R15205/55R16Difference (mm / revs)
Section width195 mm205 mm+10.0
Sidewall height126.8 mm112.8 mm-14.0
Rim diameter381.0 mm406.4 mm+25.4
Overall diameter634.5 mm631.9 mm-2.6
Circumference1,993.3 mm1,985.2 mm-8.1
Revolutions502 per km504 per km+2.0

Speedometer effect

With 205/55R16 fitted on a car calibrated for 195/65R15, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h49.8 km/h
80 km/h79.7 km/h
100 km/h99.6 km/h
120 km/h119.5 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

195/65R15 dimensions · 205/55R16 dimensions · Open in calculator