205/60R16 vs 215/45R18

215/45R18 is 0.07 in (1.7 mm) shorter than 205/60R16, a −0.26% diameter difference. With the speedometer set for 205/60R16, an indicated 60 mph is 59.8 mph on 215/45R18.

Is this a safe swap?

Diameter difference −0.26%: under 1%

By overall diameter alone, 215/45R18 is a near match for 205/60R16; 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: 205/60R16 (25.69 in) vs 215/45R18 (25.62 in)205/60R1625.69 in × 8.07 in215/45R1825.62 in × 8.46 in
Side profile and tread width, drawn to the same scale.
205/60R16 vs 215/45R18 differences
Measurement205/60R16215/45R18Difference% diff
Overall diameter25.69 in (652.4 mm)25.62 in (650.7 mm)−0.07 in (−1.7 mm)−0.26%
Sidewall height4.84 in (123.0 mm)3.81 in (96.8 mm)−1.03 in (−26.2 mm)−21.34%
Section width8.07 in (205.0 mm)8.46 in (215.0 mm)+0.39 in (+10.0 mm)+4.88%
Circumference80.69 in (2,049.6 mm)80.48 in (2,044.2 mm)−0.21 in (−5.3 mm)−0.26%
Revolutions per mile785787+2+0.26%
True speed with the speedometer calibrated for 205/60R16
IndicatedActual on 205/60R16Actual on 215/45R18Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.8 mph−0.2 mph
75 mph75.0 mph74.8 mph−0.2 mph

Ride-height change: 215/45R18 lowers the vehicle by 0.03 in (0.8 mm) at the axle (half the −1.7 mm diameter difference).

215/45R18 is 0.07 in shorter than 205/60R16 and 10 mm wider, a 0.26% difference in overall diameter.

With the speedometer calibrated for 205/60R16, an indicated 60 mph is actually 59.8 mph on 215/45R18, and revolutions per mile change from 785 to 787.

215/45R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 205/60R16.

Size pages

Other comparisons with 205/60R16

Other comparisons with 215/45R18

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