245/60R16 vs 215/55R18

215/55R18 is 0.26 in (6.7 mm) shorter than 245/60R16, a −0.96% diameter difference. With the speedometer set for 245/60R16, an indicated 60 mph is 59.4 mph on 215/55R18.

Is this a safe swap?

Diameter difference −0.96%: under 1%

By overall diameter alone, 215/55R18 is a near match for 245/60R16; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

Side profile and tread width, drawn to the same scale.

245/60R16 vs 215/55R18 differences
Measurement	245/60R16	215/55R18	Difference	% diff
Overall diameter	27.57 in (700.4 mm)	27.31 in (693.7 mm)	−0.26 in (−6.7 mm)	−0.96%
Sidewall height	5.79 in (147.0 mm)	4.66 in (118.3 mm)	−1.13 in (−28.7 mm)	−19.56%
Section width	9.65 in (245.0 mm)	8.46 in (215.0 mm)	−1.18 in (−30.0 mm)	−12.24%
Circumference	86.63 in (2,200.4 mm)	85.80 in (2,179.3 mm)	−0.83 in (−21.0 mm)	−0.96%
Revolutions per mile	731	738	+7	+0.97%

True speed with the speedometer calibrated for 245/60R16
Indicated	Actual on 245/60R16	Actual on 215/55R18	Difference
30 mph	30.0 mph	29.7 mph	−0.3 mph
60 mph	60.0 mph	59.4 mph	−0.6 mph
75 mph	75.0 mph	74.3 mph	−0.7 mph

Ride-height change: 215/55R18 lowers the vehicle by 0.13 in (3.3 mm) at the axle (half the −6.7 mm diameter difference).

215/55R18 is 0.26 in shorter than 245/60R16 and 30 mm narrower, a 0.96% difference in overall diameter.

With the speedometer calibrated for 245/60R16, an indicated 60 mph is actually 59.4 mph on 215/55R18, and revolutions per mile change from 731 to 738.

215/55R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 245/60R16.

Size pages

Other comparisons with 245/60R16

Other comparisons with 215/55R18

Source: Calculated from standard tire geometry formulas. Verified 2026-09-27. How these numbers are calculated.