Tire Size Box

355/45R19 vs 345/50R19

345/50R19 compared with 355/45R19

+3.2% diameter, −0.4" width

345/50R19 is 32.58" tall vs 31.58". More than the 3% rule of thumb, so check carefully before switching.

31.6"19" rim6.3"14.0" wide
355/45R19 (solid) compared with 345/50R19 (dashed outline), drawn to scale

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

61.9 mph

345/50R19 is +1.00 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

355/45R19345/50R19Difference%
Overall diameter31.58"32.58"+1.00"+3.2%
Section width13.98"13.58"−0.39"−2.8%
Sidewall height6.29"6.79"+0.50"+8.0%
Circumference99.21"102.36"+3.15"+3.2%
Revolutions per mile638.7619.0−19.7−3.1%

Speedometer difference

If your vehicle came with 355/45R19 and you fit 345/50R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.2 mph+2.2 mph
75 mph77.4 mph+2.4 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 355/45R19 or 345/50R19?
345/50R19 is taller by 1.00 inches (32.58" vs 31.58"). 355/45R19 is wider by 0.39 inches.
Can I replace 355/45R19 with 345/50R19?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 355/45R19), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 345/50R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

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