Tire Size Box

355/45R19 vs 355/55R19

355/55R19 compared with 355/45R19

+8.9% diameter, 0.0" width

355/55R19 is 34.37" 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 355/55R19 (dashed outline), drawn to scale

With 355/55R19 tires, when your speedometer says 60 mph you are really going

65.3 mph

355/55R19 is +2.80 inches (+8.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

355/45R19355/55R19Difference%
Overall diameter31.58"34.37"+2.80"+8.9%
Section width13.98"13.98"0.00"0.0%
Sidewall height6.29"7.69"+1.40"+22.2%
Circumference99.21"107.99"+8.78"+8.9%
Revolutions per mile638.7586.7−51.9−8.1%

Speedometer difference

If your vehicle came with 355/45R19 and you fit 355/55R19, 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 mph43.5 mph+3.5 mph
50 mph54.4 mph+4.4 mph
60 mph65.3 mph+5.3 mph
65 mph70.8 mph+5.8 mph
70 mph76.2 mph+6.2 mph
75 mph81.6 mph+6.6 mph
80 mph87.1 mph+7.1 mph

Each size on its own

Questions

Which is bigger, 355/45R19 or 355/55R19?
355/55R19 is taller by 2.80 inches (34.37" vs 31.58"). 355/45R19 is the same width.
Can I replace 355/45R19 with 355/55R19?
It is not recommended without checking carefully. The diameter difference is +8.9%, 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 355/55R19 change my speedometer?
When your speedometer reads 60 mph with 355/55R19 fitted (calibrated for 355/45R19), your real speed is 65.3 mph. Your odometer will under-count miles by about 8.9%.
Will 355/55R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.40 inches of ground clearance at the axle.

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