225/55R18 vs 225/50R19

225/50R19 is 0.11 in (2.9 mm) taller than 225/55R18, a +0.41% diameter difference. With the speedometer set for 225/55R18, an indicated 60 mph is 60.2 mph on 225/50R19.

Is this a safe swap?

Diameter difference +0.41%: under 1%

By overall diameter alone, 225/50R19 is a near match for 225/55R18; 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.

225/55R18 vs 225/50R19 differences
Measurement	225/55R18	225/50R19	Difference	% diff
Overall diameter	27.74 in (704.7 mm)	27.86 in (707.6 mm)	+0.11 in (+2.9 mm)	+0.41%
Sidewall height	4.87 in (123.8 mm)	4.43 in (112.5 mm)	−0.44 in (−11.2 mm)	−9.09%
Section width	8.86 in (225.0 mm)	8.86 in (225.0 mm)	0.00 in (0.0 mm)	0.00%
Circumference	87.16 in (2,213.9 mm)	87.52 in (2,223.0 mm)	+0.36 in (+9.1 mm)	+0.41%
Revolutions per mile	727	724	−3	−0.41%

True speed with the speedometer calibrated for 225/55R18
Indicated	Actual on 225/55R18	Actual on 225/50R19	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	75.3 mph	+0.3 mph

Ride-height change: 225/50R19 raises the vehicle by 0.06 in (1.4 mm) at the axle (half the +2.9 mm diameter difference).

225/50R19 is 0.11 in taller than 225/55R18 and the same width, a 0.41% difference in overall diameter.

With the speedometer calibrated for 225/55R18, an indicated 60 mph is actually 60.2 mph on 225/50R19, and revolutions per mile change from 727 to 724.

225/50R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 225/55R18.

Size pages

Other comparisons with 225/55R18

Other comparisons with 225/50R19

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