TireSizesFinder

265/35R18 vs 255/30R19

255/30R19 is 0.28 in (7.1 mm) shorter than 265/35R18, a −1.10% diameter difference. With the speedometer set for 265/35R18, an indicated 60 mph is 59.3 mph on 255/30R19.

Is this a safe swap?

Diameter difference −1.10%: within the ±3% guideline

By overall diameter alone, 255/30R19 falls inside the ±3% range commonly used as a guideline when replacing 265/35R18. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 265/35R18 (25.30 in) vs 255/30R19 (25.02 in)265/35R1825.30 in × 10.43 in255/30R1925.02 in × 10.04 in
Side profile and tread width, drawn to the same scale.
265/35R18 vs 255/30R19 differences
Measurement265/35R18255/30R19Difference% diff
Overall diameter25.30 in (642.7 mm)25.02 in (635.6 mm)−0.28 in (−7.1 mm)−1.10%
Sidewall height3.65 in (92.8 mm)3.01 in (76.5 mm)−0.64 in (−16.2 mm)−17.52%
Section width10.43 in (265.0 mm)10.04 in (255.0 mm)−0.39 in (−10.0 mm)−3.77%
Circumference79.49 in (2,019.1 mm)78.61 in (1,996.8 mm)−0.88 in (−22.3 mm)−1.10%
Revolutions per mile797806+9+1.12%
True speed with the speedometer calibrated for 265/35R18
IndicatedActual on 265/35R18Actual on 255/30R19Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.3 mph−0.7 mph
75 mph75.0 mph74.2 mph−0.8 mph

Ride-height change: 255/30R19 lowers the vehicle by 0.14 in (3.6 mm) at the axle (half the −7.1 mm diameter difference).

255/30R19 is 0.28 in shorter than 265/35R18 and 10 mm narrower, a 1.10% difference in overall diameter.

With the speedometer calibrated for 265/35R18, an indicated 60 mph is actually 59.3 mph on 255/30R19, and revolutions per mile change from 797 to 806.

255/30R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 265/35R18.

Size pages

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