Tire Size Box

295/50R18 vs 295/55R18

295/55R18 compared with 295/50R18

+3.9% diameter, 0.0" width

295/55R18 is 30.78" tall vs 29.61". More than the 3% rule of thumb, so check carefully before switching.

29.6"18" rim5.8"11.6" wide
295/50R18 (solid) compared with 295/55R18 (dashed outline), drawn to scale

With 295/55R18 tires, when your speedometer says 60 mph you are really going

62.4 mph

295/55R18 is +1.16 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/50R18295/55R18Difference%
Overall diameter29.61"30.78"+1.16"+3.9%
Section width11.61"11.61"0.00"0.0%
Sidewall height5.81"6.39"+0.58"+10.0%
Circumference93.04"96.68"+3.65"+3.9%
Revolutions per mile681.0655.3−25.7−3.8%

Speedometer difference

If your vehicle came with 295/50R18 and you fit 295/55R18, 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 mph67.5 mph+2.5 mph
70 mph72.7 mph+2.7 mph
75 mph77.9 mph+2.9 mph
80 mph83.1 mph+3.1 mph

Each size on its own

Questions

Which is bigger, 295/50R18 or 295/55R18?
295/55R18 is taller by 1.16 inches (30.78" vs 29.61"). 295/50R18 is the same width.
Can I replace 295/50R18 with 295/55R18?
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 295/55R18 change my speedometer?
When your speedometer reads 60 mph with 295/55R18 fitted (calibrated for 295/50R18), your real speed is 62.4 mph. Your odometer will under-count miles by about 3.9%.
Will 295/55R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.58 inches of ground clearance at the axle.

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