ElpiAuto

Tire size comparison

245/35R19 vs 245/40R19

245/40R19 is 0.96″ (25 mm) taller than 245/35R19, a 3.7% difference in overall diameter — outside the ±3% band, so expect the speedometer to drift and check for rubbing before fitting.

25.75″26.72″A  245/35R19B  245/40R19Both sizes to scale · dimension lines in inches
Measurement245/35R19245/40R19Difference%
Overall diameter25.75″26.72″+0.96″+3.7%
Section width9.65″9.65″
Sidewall height3.38″3.86″+0.48″+14.3%
Circumference80.90″83.93″+3.03″+3.7%
Revs per mile783.2754.9−28.3−3.6%
Revs per km486.6469.1−17.6−3.6%

Speedometer: with 245/35R19 as the original, 245/40R19 makes an indicated 60 mph really about 62.2 mph, and the axle sits ~0.48″ higher.

Reading this comparison

The overall diameter is what matters here: 245/40R19 is the taller tire. It sets ride height, gearing and how far the tire travels per revolution — which is what the speedometer and odometer count. Width and sidewall change fit and feel (a wider tire needs a wider wheel and more clearance; a shorter sidewall sharpens steering) but not the gearing.

Figures are geometric estimates from the size codes; real moulded tires vary by brand by 1–3%. Confirm load rating, wheel width and physical clearance on your vehicle before fitting. To compare any other two sizes, use the tire size comparison tool; to decode one size and see what else fits its wheel, the tire size calculator.

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