TireSizesFinder

215/60R16 vs 225/45R18

225/45R18 is 0.19 in (4.7 mm) shorter than 215/60R16, a −0.71% diameter difference. With the speedometer set for 215/60R16, an indicated 60 mph is 59.6 mph on 225/45R18.

Is this a safe swap?

Diameter difference −0.71%: under 1%

By overall diameter alone, 225/45R18 is a near match for 215/60R16; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 215/60R16 (26.16 in) vs 225/45R18 (25.97 in)215/60R1626.16 in × 8.46 in225/45R1825.97 in × 8.86 in
Side profile and tread width, drawn to the same scale.
215/60R16 vs 225/45R18 differences
Measurement215/60R16225/45R18Difference% diff
Overall diameter26.16 in (664.4 mm)25.97 in (659.7 mm)−0.19 in (−4.7 mm)−0.71%
Sidewall height5.08 in (129.0 mm)3.99 in (101.3 mm)−1.09 in (−27.7 mm)−21.51%
Section width8.46 in (215.0 mm)8.86 in (225.0 mm)+0.39 in (+10.0 mm)+4.65%
Circumference82.18 in (2,087.3 mm)81.59 in (2,072.5 mm)−0.58 in (−14.8 mm)−0.71%
Revolutions per mile771777+5+0.71%
True speed with the speedometer calibrated for 215/60R16
IndicatedActual on 215/60R16Actual on 225/45R18Difference
30 mph30.0 mph29.8 mph−0.2 mph
60 mph60.0 mph59.6 mph−0.4 mph
75 mph75.0 mph74.5 mph−0.5 mph

Ride-height change: 225/45R18 lowers the vehicle by 0.09 in (2.3 mm) at the axle (half the −4.7 mm diameter difference).

225/45R18 is 0.19 in shorter than 215/60R16 and 10 mm wider, a 0.71% difference in overall diameter.

With the speedometer calibrated for 215/60R16, an indicated 60 mph is actually 59.6 mph on 225/45R18, and revolutions per mile change from 771 to 777.

225/45R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 215/60R16.

Size pages

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Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.