215/65R16 vs 215/70R15

Switching from 215/65R16 to 215/70R15 decreases the overall diameter by 3.9 mm (0.6%). That is within the usual ±3% guideline.

215/65R16215/70R15Difference (mm / revs)
Section width215 mm215 mm+0.0
Sidewall height139.8 mm150.5 mm+10.7
Rim diameter406.4 mm381.0 mm-25.4
Overall diameter685.9 mm682.0 mm-3.9
Circumference2,154.8 mm2,142.6 mm-12.2
Revolutions464 per km467 per km+3.0

Speedometer effect

With 215/70R15 fitted on a car calibrated for 215/65R16, the real speed when the speedometer shows:

Speedometer showsActual speed
50 km/h49.7 km/h
80 km/h79.5 km/h
100 km/h99.4 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

215/65R16 dimensions · 215/70R15 dimensions · Open in calculator