Tire Size Box

235/35R19 vs 235/40R19

235/40R19 compared with 235/35R19

+3.6% diameter, 0.0" width

235/40R19 is 26.40" tall vs 25.48". More than the 3% rule of thumb, so check carefully before switching.

25.5"19" rim3.2"9.3" wide
235/35R19 (solid) compared with 235/40R19 (dashed outline), drawn to scale

With 235/40R19 tires, when your speedometer says 60 mph you are really going

62.2 mph

235/40R19 is +0.93 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/35R19235/40R19Difference%
Overall diameter25.48"26.40"+0.93"+3.6%
Section width9.25"9.25"0.00"0.0%
Sidewall height3.24"3.70"+0.46"+14.3%
Circumference80.04"82.94"+2.91"+3.6%
Revolutions per mile791.6763.9−27.7−3.5%

Speedometer difference

If your vehicle came with 235/35R19 and you fit 235/40R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 235/35R19 or 235/40R19?
235/40R19 is taller by 0.93 inches (26.40" vs 25.48"). 235/35R19 is the same width.
Can I replace 235/35R19 with 235/40R19?
It is not recommended without checking carefully. The diameter difference is +3.6%, more than the 3% most shops and makers allow. It will throw off the speedometer and may affect ABS, stability control and clearance.
How much will 235/40R19 change my speedometer?
When your speedometer reads 60 mph with 235/40R19 fitted (calibrated for 235/35R19), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 235/40R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.46 inches of ground clearance at the axle.

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