265/50R20 vs 265/70R16

Switching from 265/50R20 to 265/70R16 increases the overall diameter by 4.4 mm (0.6%). That is within the usual ±3% guideline.

265/50R20265/70R16Difference (mm / revs)
Section width265 mm265 mm+0.0
Sidewall height132.5 mm185.5 mm+53.0
Rim diameter508.0 mm406.4 mm-101.6
Overall diameter773.0 mm777.4 mm+4.4
Circumference2,428.5 mm2,442.3 mm+13.8
Revolutions412 per km409 per km-3.0

Speedometer effect

With 265/70R16 fitted on a car calibrated for 265/50R20, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.3 km/h
80 km/h80.5 km/h
100 km/h100.6 km/h
120 km/h120.7 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

265/50R20 dimensions · 265/70R16 dimensions · Open in calculator