215/60R17 vs 235/60R16

Switching from 215/60R17 to 235/60R16 decreases the overall diameter by 1.4 mm (0.2%). That is within the usual ±3% guideline.

215/60R17235/60R16Difference (mm / revs)
Section width215 mm235 mm+20.0
Sidewall height129.0 mm141.0 mm+12.0
Rim diameter431.8 mm406.4 mm-25.4
Overall diameter689.8 mm688.4 mm-1.4
Circumference2,167.1 mm2,162.7 mm-4.4
Revolutions461 per km462 per km+1.0

Speedometer effect

With 235/60R16 fitted on a car calibrated for 215/60R17, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h49.9 km/h
80 km/h79.8 km/h
100 km/h99.8 km/h
120 km/h119.8 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

215/60R17 dimensions · 235/60R16 dimensions · Open in calculator