Tire Size Box

235/40R19 vs 235/50R19

235/50R19 compared with 235/40R19

+7.0% diameter, 0.0" width

235/50R19 is 28.25" tall vs 26.40". More than the 3% rule of thumb, so check carefully before switching.

26.4"19" rim3.7"9.3" wide
235/40R19 (solid) compared with 235/50R19 (dashed outline), drawn to scale

With 235/50R19 tires, when your speedometer says 60 mph you are really going

64.2 mph

235/50R19 is +1.85 inches (+7.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/40R19235/50R19Difference%
Overall diameter26.40"28.25"+1.85"+7.0%
Section width9.25"9.25"0.00"0.0%
Sidewall height3.70"4.63"+0.93"+25.0%
Circumference82.94"88.76"+5.81"+7.0%
Revolutions per mile763.9713.9−50.0−6.5%

Speedometer difference

If your vehicle came with 235/40R19 and you fit 235/50R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.6 mph+4.6 mph
70 mph74.9 mph+4.9 mph
75 mph80.3 mph+5.3 mph
80 mph85.6 mph+5.6 mph

Each size on its own

Questions

Which is bigger, 235/40R19 or 235/50R19?
235/50R19 is taller by 1.85 inches (28.25" vs 26.40"). 235/40R19 is the same width.
Can I replace 235/40R19 with 235/50R19?
It is not recommended without checking carefully. The diameter difference is +7.0%, 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 235/50R19 change my speedometer?
When your speedometer reads 60 mph with 235/50R19 fitted (calibrated for 235/40R19), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.0%.
Will 235/50R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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