225/55R19 vs 255/50R19

255/50R19 is 0.30 in (7.5 mm) taller than 225/55R19, a +1.03% diameter difference. With the speedometer set for 225/55R19, an indicated 60 mph is 60.6 mph on 255/50R19.

Is this a safe swap?

Diameter difference +1.03%: within the ±3% guideline

By overall diameter alone, 255/50R19 falls inside the ±3% range commonly used as a guideline when replacing 225/55R19. 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.

225/55R19 vs 255/50R19 differences
Measurement	225/55R19	255/50R19	Difference	% diff
Overall diameter	28.74 in (730.1 mm)	29.04 in (737.6 mm)	+0.30 in (+7.5 mm)	+1.03%
Sidewall height	4.87 in (123.8 mm)	5.02 in (127.5 mm)	+0.15 in (+3.8 mm)	+3.03%
Section width	8.86 in (225.0 mm)	10.04 in (255.0 mm)	+1.18 in (+30.0 mm)	+13.33%
Circumference	90.30 in (2,293.7 mm)	91.23 in (2,317.2 mm)	+0.93 in (+23.6 mm)	+1.03%
Revolutions per mile	702	695	−7	−1.02%

True speed with the speedometer calibrated for 225/55R19
Indicated	Actual on 225/55R19	Actual on 255/50R19	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	75.8 mph	+0.8 mph

Ride-height change: 255/50R19 raises the vehicle by 0.15 in (3.8 mm) at the axle (half the +7.5 mm diameter difference).

255/50R19 is 0.30 in taller than 225/55R19 and 30 mm wider, a 1.03% difference in overall diameter.

With the speedometer calibrated for 225/55R19, an indicated 60 mph is actually 60.6 mph on 255/50R19, and revolutions per mile change from 702 to 695.

Both sizes mount on 19-inch wheels.

Size pages

Other comparisons with 225/55R19

Other comparisons with 255/50R19

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