TireSizesFinder

285/40R18 vs 285/35R19

285/35R19 is 0.12 in (3.1 mm) shorter than 285/40R18, a −0.45% diameter difference. With the speedometer set for 285/40R18, an indicated 60 mph is 59.7 mph on 285/35R19.

Is this a safe swap?

Diameter difference −0.45%: under 1%

By overall diameter alone, 285/35R19 is a near match for 285/40R18; the speedometer changes by less than 1%. This check uses diameter only. It does not assess load index, speed rating, wheel width or clearance.

To-scale drawing: 285/40R18 (26.98 in) vs 285/35R19 (26.85 in)285/40R1826.98 in × 11.22 in285/35R1926.85 in × 11.22 in
Side profile and tread width, drawn to the same scale.
285/40R18 vs 285/35R19 differences
Measurement285/40R18285/35R19Difference% diff
Overall diameter26.98 in (685.2 mm)26.85 in (682.1 mm)−0.12 in (−3.1 mm)−0.45%
Sidewall height4.49 in (114.0 mm)3.93 in (99.8 mm)−0.56 in (−14.2 mm)−12.50%
Section width11.22 in (285.0 mm)11.22 in (285.0 mm)0.00 in (0.0 mm)0.00%
Circumference84.75 in (2,152.6 mm)84.37 in (2,142.9 mm)−0.38 in (−9.7 mm)−0.45%
Revolutions per mile748751+3+0.45%
True speed with the speedometer calibrated for 285/40R18
IndicatedActual on 285/40R18Actual on 285/35R19Difference
30 mph30.0 mph29.9 mph−0.1 mph
60 mph60.0 mph59.7 mph−0.3 mph
75 mph75.0 mph74.7 mph−0.3 mph

Ride-height change: 285/35R19 lowers the vehicle by 0.06 in (1.6 mm) at the axle (half the −3.1 mm diameter difference).

285/35R19 is 0.12 in shorter than 285/40R18 and the same width, a 0.45% difference in overall diameter.

With the speedometer calibrated for 285/40R18, an indicated 60 mph is actually 59.7 mph on 285/35R19, and revolutions per mile change from 748 to 751.

285/35R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 285/40R18.

Size pages

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