245/55R18 vs 225/55R19

225/55R19 is 0.13 in (3.4 mm) taller than 245/55R18, a +0.47% diameter difference. With the speedometer set for 245/55R18, an indicated 60 mph is 60.3 mph on 225/55R19.

Is this a safe swap?

Diameter difference +0.47%: under 1%

By overall diameter alone, 225/55R19 is a near match for 245/55R18; 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.

245/55R18 vs 225/55R19 differences
Measurement	245/55R18	225/55R19	Difference	% diff
Overall diameter	28.61 in (726.7 mm)	28.74 in (730.1 mm)	+0.13 in (+3.4 mm)	+0.47%
Sidewall height	5.31 in (134.8 mm)	4.87 in (123.8 mm)	−0.43 in (−11.0 mm)	−8.16%
Section width	9.65 in (245.0 mm)	8.86 in (225.0 mm)	−0.79 in (−20.0 mm)	−8.16%
Circumference	89.88 in (2,283.0 mm)	90.30 in (2,293.7 mm)	+0.42 in (+10.7 mm)	+0.47%
Revolutions per mile	705	702	−3	−0.47%

True speed with the speedometer calibrated for 245/55R18
Indicated	Actual on 245/55R18	Actual on 225/55R19	Difference
30 mph	30.0 mph	30.1 mph	+0.1 mph
60 mph	60.0 mph	60.3 mph	+0.3 mph
75 mph	75.0 mph	75.4 mph	+0.4 mph

Ride-height change: 225/55R19 raises the vehicle by 0.07 in (1.7 mm) at the axle (half the +3.4 mm diameter difference).

225/55R19 is 0.13 in taller than 245/55R18 and 20 mm narrower, a 0.47% difference in overall diameter.

With the speedometer calibrated for 245/55R18, an indicated 60 mph is actually 60.3 mph on 225/55R19, and revolutions per mile change from 705 to 702.

225/55R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 245/55R18.

Size pages

Other comparisons with 245/55R18

Other comparisons with 225/55R19

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