215/60R17 vs 235/55R17

Switching from 215/60R17 to 235/55R17 increases the overall diameter by 0.5 mm (0.1%). That is within the usual ±3% guideline.

215/60R17235/55R17Difference (mm / revs)
Section width215 mm235 mm+20.0
Sidewall height129.0 mm129.2 mm+0.2
Rim diameter431.8 mm431.8 mm+0.0
Overall diameter689.8 mm690.3 mm+0.5
Circumference2,167.1 mm2,168.6 mm+1.5
Revolutions461 per km461 per km+0.0

Speedometer effect

With 235/55R17 fitted on a car calibrated for 215/60R17, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h50.0 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

215/60R17 dimensions · 235/55R17 dimensions · Open in calculator