Tire Size Box

355/40R19 vs 355/50R19

355/50R19 compared with 355/40R19

+9.3% diameter, 0.0" width

355/50R19 is 32.98" tall vs 30.18". More than the 3% rule of thumb, so check carefully before switching.

30.2"19" rim5.6"14.0" wide
355/40R19 (solid) compared with 355/50R19 (dashed outline), drawn to scale

With 355/50R19 tires, when your speedometer says 60 mph you are really going

65.6 mph

355/50R19 is +2.80 inches (+9.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

355/40R19355/50R19Difference%
Overall diameter30.18"32.98"+2.80"+9.3%
Section width13.98"13.98"0.00"0.0%
Sidewall height5.59"6.99"+1.40"+25.0%
Circumference94.82"103.60"+8.78"+9.3%
Revolutions per mile668.2611.6−56.6−8.5%

Speedometer difference

If your vehicle came with 355/40R19 and you fit 355/50R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.9 mph+1.9 mph
30 mph32.8 mph+2.8 mph
40 mph43.7 mph+3.7 mph
50 mph54.6 mph+4.6 mph
60 mph65.6 mph+5.6 mph
65 mph71.0 mph+6.0 mph
70 mph76.5 mph+6.5 mph
75 mph81.9 mph+6.9 mph
80 mph87.4 mph+7.4 mph

Each size on its own

Questions

Which is bigger, 355/40R19 or 355/50R19?
355/50R19 is taller by 2.80 inches (32.98" vs 30.18"). 355/40R19 is the same width.
Can I replace 355/40R19 with 355/50R19?
It is not recommended without checking carefully. The diameter difference is +9.3%, 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 355/50R19 change my speedometer?
When your speedometer reads 60 mph with 355/50R19 fitted (calibrated for 355/40R19), your real speed is 65.6 mph. Your odometer will under-count miles by about 9.3%.
Will 355/50R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.40 inches of ground clearance at the axle.

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