215/65R17 vs 215/70R16

Switching from 215/65R17 to 215/70R16 decreases the overall diameter by 3.9 mm (0.5%). That is within the usual ±3% guideline.

215/65R17215/70R16Difference (mm / revs)
Section width215 mm215 mm+0.0
Sidewall height139.8 mm150.5 mm+10.7
Rim diameter431.8 mm406.4 mm-25.4
Overall diameter711.3 mm707.4 mm-3.9
Circumference2,234.6 mm2,222.4 mm-12.2
Revolutions448 per km450 per km+2.0

Speedometer effect

With 215/70R16 fitted on a car calibrated for 215/65R17, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h49.7 km/h
80 km/h79.6 km/h
100 km/h99.5 km/h
120 km/h119.3 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

215/65R17 dimensions · 215/70R16 dimensions · Open in calculator