Tire Size Box

315/50R22 vs 315/55R22

315/55R22 compared with 315/50R22

+3.6% diameter, 0.0" width

315/55R22 is 35.64" tall vs 34.40". More than the 3% rule of thumb, so check carefully before switching.

34.4"22" rim6.2"12.4" wide
315/50R22 (solid) compared with 315/55R22 (dashed outline), drawn to scale

With 315/55R22 tires, when your speedometer says 60 mph you are really going

62.2 mph

315/55R22 is +1.24 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

315/50R22315/55R22Difference%
Overall diameter34.40"35.64"+1.24"+3.6%
Section width12.40"12.40"0.00"0.0%
Sidewall height6.20"6.82"+0.62"+10.0%
Circumference108.08"111.97"+3.90"+3.6%
Revolutions per mile586.3565.9−20.4−3.5%

Speedometer difference

If your vehicle came with 315/50R22 and you fit 315/55R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 315/50R22 or 315/55R22?
315/55R22 is taller by 1.24 inches (35.64" vs 34.40"). 315/50R22 is the same width.
Can I replace 315/50R22 with 315/55R22?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 315/55R22 change my speedometer?
When your speedometer reads 60 mph with 315/55R22 fitted (calibrated for 315/50R22), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 315/55R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.62 inches of ground clearance at the axle.

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