TireSizesFinder

235/55R19 vs 255/55R19

255/55R19 is 0.87 in (22.0 mm) taller than 235/55R19, a +2.97% diameter difference. With the speedometer set for 235/55R19, an indicated 60 mph is 61.8 mph on 255/55R19.

Is this a safe swap?

Diameter difference +2.97%: within the ±3% guideline

By overall diameter alone, 255/55R19 falls inside the ±3% range commonly used as a guideline when replacing 235/55R19. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 235/55R19 (29.18 in) vs 255/55R19 (30.04 in)235/55R1929.18 in × 9.25 in255/55R1930.04 in × 10.04 in
Side profile and tread width, drawn to the same scale.
235/55R19 vs 255/55R19 differences
Measurement235/55R19255/55R19Difference% diff
Overall diameter29.18 in (741.1 mm)30.04 in (763.1 mm)+0.87 in (+22.0 mm)+2.97%
Sidewall height5.09 in (129.3 mm)5.52 in (140.3 mm)+0.43 in (+11.0 mm)+8.51%
Section width9.25 in (235.0 mm)10.04 in (255.0 mm)+0.79 in (+20.0 mm)+8.51%
Circumference91.66 in (2,328.2 mm)94.38 in (2,397.3 mm)+2.72 in (+69.1 mm)+2.97%
Revolutions per mile691671−20−2.88%
True speed with the speedometer calibrated for 235/55R19
IndicatedActual on 235/55R19Actual on 255/55R19Difference
30 mph30.0 mph30.9 mph+0.9 mph
60 mph60.0 mph61.8 mph+1.8 mph
75 mph75.0 mph77.2 mph+2.2 mph

Ride-height change: 255/55R19 raises the vehicle by 0.43 in (11.0 mm) at the axle (half the +22.0 mm diameter difference).

255/55R19 is 0.87 in taller than 235/55R19 and 20 mm wider, a 2.97% difference in overall diameter.

With the speedometer calibrated for 235/55R19, an indicated 60 mph is actually 61.8 mph on 255/55R19, and revolutions per mile change from 691 to 671.

Both sizes mount on 19-inch wheels.

Size pages

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Source: Calculated from standard tire geometry formulas. Verified . How these numbers are calculated.