225/35R19 vs 265/35R18

Switching from 225/35R19 to 265/35R18 increases the overall diameter by 2.6 mm (0.4%). That is within the usual ±3% guideline.

225/35R19265/35R18Difference (mm / revs)
Section width225 mm265 mm+40.0
Sidewall height78.8 mm92.8 mm+14.0
Rim diameter482.6 mm457.2 mm-25.4
Overall diameter640.1 mm642.7 mm+2.6
Circumference2,010.9 mm2,019.1 mm+8.2
Revolutions497 per km495 per km-2.0

Speedometer effect

With 265/35R18 fitted on a car calibrated for 225/35R19, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.2 km/h
80 km/h80.3 km/h
100 km/h100.4 km/h
120 km/h120.5 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

225/35R19 dimensions · 265/35R18 dimensions · Open in calculator