225/50R17 vs 245/35R19

Switching from 225/50R17 to 245/35R19 decreases the overall diameter by 2.7 mm (0.4%). That is within the usual ±3% guideline.

225/50R17245/35R19Difference (mm / revs)
Section width225 mm245 mm+20.0
Sidewall height112.5 mm85.8 mm-26.7
Rim diameter431.8 mm482.6 mm+50.8
Overall diameter656.8 mm654.1 mm-2.7
Circumference2,063.4 mm2,054.9 mm-8.5
Revolutions485 per km487 per km+2.0

Speedometer effect

With 245/35R19 fitted on a car calibrated for 225/50R17, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h49.8 km/h
80 km/h79.7 km/h
100 km/h99.6 km/h
120 km/h119.5 km/h

Smaller tires make the speedometer read higher than the actual speed. Most speedometers also read slightly high from the factory.

Before you change size

225/50R17 dimensions · 245/35R19 dimensions · Open in calculator