Tire Size Box

345/40R19 vs 345/50R19

345/50R19 compared with 345/40R19

+9.1% diameter, 0.0" width

345/50R19 is 32.58" tall vs 29.87". More than the 3% rule of thumb, so check carefully before switching.

29.9"19" rim5.4"13.6" wide
345/40R19 (solid) compared with 345/50R19 (dashed outline), drawn to scale

With 345/50R19 tires, when your speedometer says 60 mph you are really going

65.5 mph

345/50R19 is +2.72 inches (+9.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

345/40R19345/50R19Difference%
Overall diameter29.87"32.58"+2.72"+9.1%
Section width13.58"13.58"0.00"0.0%
Sidewall height5.43"6.79"+1.36"+25.0%
Circumference93.83"102.36"+8.53"+9.1%
Revolutions per mile675.3619.0−56.3−8.3%

Speedometer difference

If your vehicle came with 345/40R19 and you fit 345/50R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.8 mph+1.8 mph
30 mph32.7 mph+2.7 mph
40 mph43.6 mph+3.6 mph
50 mph54.5 mph+4.5 mph
60 mph65.5 mph+5.5 mph
65 mph70.9 mph+5.9 mph
70 mph76.4 mph+6.4 mph
75 mph81.8 mph+6.8 mph
80 mph87.3 mph+7.3 mph

Each size on its own

Questions

Which is bigger, 345/40R19 or 345/50R19?
345/50R19 is taller by 2.72 inches (32.58" vs 29.87"). 345/40R19 is the same width.
Can I replace 345/40R19 with 345/50R19?
It is not recommended without checking carefully. The diameter difference is +9.1%, 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 345/50R19 change my speedometer?
When your speedometer reads 60 mph with 345/50R19 fitted (calibrated for 345/40R19), your real speed is 65.5 mph. Your odometer will under-count miles by about 9.1%.
Will 345/50R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.36 inches of ground clearance at the axle.

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