245/65R16 vs 225/60R18

225/60R18 is 0.09 in (2.3 mm) taller than 245/65R16, a +0.32% diameter difference. With the speedometer set for 245/65R16, an indicated 60 mph is 60.2 mph on 225/60R18.

Is this a safe swap?

Diameter difference +0.32%: under 1%

By overall diameter alone, 225/60R18 is a near match for 245/65R16; 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.

245/65R16 vs 225/60R18 differences
Measurement	245/65R16	225/60R18	Difference	% diff
Overall diameter	28.54 in (724.9 mm)	28.63 in (727.2 mm)	+0.09 in (+2.3 mm)	+0.32%
Sidewall height	6.27 in (159.3 mm)	5.31 in (135.0 mm)	−0.95 in (−24.2 mm)	−15.23%
Section width	9.65 in (245.0 mm)	8.86 in (225.0 mm)	−0.79 in (−20.0 mm)	−8.16%
Circumference	89.66 in (2,277.3 mm)	89.94 in (2,284.6 mm)	+0.28 in (+7.2 mm)	+0.32%
Revolutions per mile	707	704	−2	−0.32%

True speed with the speedometer calibrated for 245/65R16
Indicated	Actual on 245/65R16	Actual on 225/60R18	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.2 mph	+0.2 mph
75 mph	75.0 mph	75.2 mph	+0.2 mph

Ride-height change: 225/60R18 raises the vehicle by 0.05 in (1.2 mm) at the axle (half the +2.3 mm diameter difference).

225/60R18 is 0.09 in taller than 245/65R16 and 20 mm narrower, a 0.32% difference in overall diameter.

With the speedometer calibrated for 245/65R16, an indicated 60 mph is actually 60.2 mph on 225/60R18, and revolutions per mile change from 707 to 704.

225/60R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 245/65R16.

Size pages

Other comparisons with 245/65R16

Other comparisons with 225/60R18

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