265/60R18 vs 265/70R16

Switching from 265/60R18 to 265/70R16 increases the overall diameter by 2.2 mm (0.3%). That is within the usual ±3% guideline.

265/60R18265/70R16Difference (mm / revs)
Section width265 mm265 mm+0.0
Sidewall height159.0 mm185.5 mm+26.5
Rim diameter457.2 mm406.4 mm-50.8
Overall diameter775.2 mm777.4 mm+2.2
Circumference2,435.4 mm2,442.3 mm+6.9
Revolutions411 per km409 per km-2.0

Speedometer effect

With 265/70R16 fitted on a car calibrated for 265/60R18, 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

265/60R18 dimensions · 265/70R16 dimensions · Open in calculator