Tire Size Box

315/50R19 vs 315/55R19

315/55R19 compared with 315/50R19

+3.9% diameter, 0.0" width

315/55R19 is 32.64" tall vs 31.40". More than the 3% rule of thumb, so check carefully before switching.

31.4"19" rim6.2"12.4" wide
315/50R19 (solid) compared with 315/55R19 (dashed outline), drawn to scale

With 315/55R19 tires, when your speedometer says 60 mph you are really going

62.4 mph

315/55R19 is +1.24 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

315/50R19315/55R19Difference%
Overall diameter31.40"32.64"+1.24"+3.9%
Section width12.40"12.40"0.00"0.0%
Sidewall height6.20"6.82"+0.62"+10.0%
Circumference98.65"102.55"+3.90"+3.9%
Revolutions per mile642.3617.9−24.4−3.8%

Speedometer difference

If your vehicle came with 315/50R19 and you fit 315/55R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.2 mph+1.2 mph
40 mph41.6 mph+1.6 mph
50 mph52.0 mph+2.0 mph
60 mph62.4 mph+2.4 mph
65 mph67.6 mph+2.6 mph
70 mph72.8 mph+2.8 mph
75 mph78.0 mph+3.0 mph
80 mph83.2 mph+3.2 mph

Each size on its own

Questions

Which is bigger, 315/50R19 or 315/55R19?
315/55R19 is taller by 1.24 inches (32.64" vs 31.40"). 315/50R19 is the same width.
Can I replace 315/50R19 with 315/55R19?
It is not recommended without checking carefully. The diameter difference is +3.9%, 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 315/55R19 change my speedometer?
When your speedometer reads 60 mph with 315/55R19 fitted (calibrated for 315/50R19), your real speed is 62.4 mph. Your odometer will under-count miles by about 3.9%.
Will 315/55R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.62 inches of ground clearance at the axle.

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