215/65R16 vs 255/40R19

Switching from 215/65R16 to 255/40R19 increases the overall diameter by 0.7 mm (0.1%). That is within the usual ±3% guideline.

215/65R16255/40R19Difference (mm / revs)
Section width215 mm255 mm+40.0
Sidewall height139.8 mm102.0 mm-37.8
Rim diameter406.4 mm482.6 mm+76.2
Overall diameter685.9 mm686.6 mm+0.7
Circumference2,154.8 mm2,157.0 mm+2.2
Revolutions464 per km464 per km+0.0

Speedometer effect

With 255/40R19 fitted on a car calibrated for 215/65R16, the real speed when the speedometer shows:

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

215/65R16 dimensions · 255/40R19 dimensions · Open in calculator