265/65R18 vs 265/75R16

Switching from 265/65R18 to 265/75R16 increases the overall diameter by 2.2 mm (0.3%). That is within the usual ±3% guideline.

265/65R18265/75R16Difference (mm / revs)
Section width265 mm265 mm+0.0
Sidewall height172.2 mm198.8 mm+26.6
Rim diameter457.2 mm406.4 mm-50.8
Overall diameter801.7 mm803.9 mm+2.2
Circumference2,518.6 mm2,525.5 mm+6.9
Revolutions397 per km396 per km-1.0

Speedometer effect

With 265/75R16 fitted on a car calibrated for 265/65R18, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.1 km/h
80 km/h80.2 km/h
100 km/h100.3 km/h
120 km/h120.3 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

265/65R18 dimensions · 265/75R16 dimensions · Open in calculator