TireSizesFinder

245/40R18 vs 235/35R19

235/35R19 is 0.24 in (6.1 mm) shorter than 245/40R18, a −0.93% diameter difference. With the speedometer set for 245/40R18, an indicated 60 mph is 59.4 mph on 235/35R19.

Is this a safe swap?

Diameter difference −0.93%: under 1%

By overall diameter alone, 235/35R19 is a near match for 245/40R18; 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: 245/40R18 (25.72 in) vs 235/35R19 (25.48 in)245/40R1825.72 in × 9.65 in235/35R1925.48 in × 9.25 in
Side profile and tread width, drawn to the same scale.
245/40R18 vs 235/35R19 differences
Measurement245/40R18235/35R19Difference% diff
Overall diameter25.72 in (653.2 mm)25.48 in (647.1 mm)−0.24 in (−6.1 mm)−0.93%
Sidewall height3.86 in (98.0 mm)3.24 in (82.3 mm)−0.62 in (−15.7 mm)−16.07%
Section width9.65 in (245.0 mm)9.25 in (235.0 mm)−0.39 in (−10.0 mm)−4.08%
Circumference80.79 in (2,052.1 mm)80.04 in (2,032.9 mm)−0.75 in (−19.2 mm)−0.93%
Revolutions per mile784792+7+0.94%
True speed with the speedometer calibrated for 245/40R18
IndicatedActual on 245/40R18Actual on 235/35R19Difference
30 mph30.0 mph29.7 mph−0.3 mph
60 mph60.0 mph59.4 mph−0.6 mph
75 mph75.0 mph74.3 mph−0.7 mph

Ride-height change: 235/35R19 lowers the vehicle by 0.12 in (3.1 mm) at the axle (half the −6.1 mm diameter difference).

235/35R19 is 0.24 in shorter than 245/40R18 and 10 mm narrower, a 0.93% difference in overall diameter.

With the speedometer calibrated for 245/40R18, an indicated 60 mph is actually 59.4 mph on 235/35R19, and revolutions per mile change from 784 to 792.

235/35R19 mounts on a 19-inch wheel, a plus-1 fitment from the 18-inch wheel of 245/40R18.

Size pages

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