225/75R16 vs 245/60R18

245/60R18 is 0.29 in (7.3 mm) taller than 225/75R16, a +0.98% diameter difference. With the speedometer set for 225/75R16, an indicated 60 mph is 60.6 mph on 245/60R18.

Is this a safe swap?

Diameter difference +0.98%: under 1%

By overall diameter alone, 245/60R18 is a near match for 225/75R16; 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.

225/75R16 vs 245/60R18 differences
Measurement	225/75R16	245/60R18	Difference	% diff
Overall diameter	29.29 in (743.9 mm)	29.57 in (751.2 mm)	+0.29 in (+7.3 mm)	+0.98%
Sidewall height	6.64 in (168.8 mm)	5.79 in (147.0 mm)	−0.86 in (−21.7 mm)	−12.89%
Section width	8.86 in (225.0 mm)	9.65 in (245.0 mm)	+0.79 in (+20.0 mm)	+8.89%
Circumference	92.01 in (2,337.0 mm)	92.91 in (2,360.0 mm)	+0.90 in (+22.9 mm)	+0.98%
Revolutions per mile	689	682	−7	−0.97%

True speed with the speedometer calibrated for 225/75R16
Indicated	Actual on 225/75R16	Actual on 245/60R18	Difference
30 mph	30.0 mph	30.3 mph	+0.3 mph
60 mph	60.0 mph	60.6 mph	+0.6 mph
75 mph	75.0 mph	75.7 mph	+0.7 mph

Ride-height change: 245/60R18 raises the vehicle by 0.14 in (3.7 mm) at the axle (half the +7.3 mm diameter difference).

245/60R18 is 0.29 in taller than 225/75R16 and 20 mm wider, a 0.98% difference in overall diameter.

With the speedometer calibrated for 225/75R16, an indicated 60 mph is actually 60.6 mph on 245/60R18, and revolutions per mile change from 689 to 682.

245/60R18 mounts on a 18-inch wheel, a plus-2 fitment from the 16-inch wheel of 225/75R16.

Size pages

Other comparisons with 225/75R16

Other comparisons with 245/60R18

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