Tire Size Box

265/55R15 vs 285/55R15

285/55R15 compared with 265/55R15

+3.3% diameter, +0.8" width

285/55R15 is 27.34" tall vs 26.48". More than the 3% rule of thumb, so check carefully before switching.

26.5"15" rim5.7"10.4" wide
265/55R15 (solid) compared with 285/55R15 (dashed outline), drawn to scale

With 285/55R15 tires, when your speedometer says 60 mph you are really going

62.0 mph

285/55R15 is +0.87 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/55R15285/55R15Difference%
Overall diameter26.48"27.34"+0.87"+3.3%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height5.74"6.17"+0.43"+7.5%
Circumference83.18"85.90"+2.72"+3.3%
Revolutions per mile761.7737.6−24.1−3.2%

Speedometer difference

If your vehicle came with 265/55R15 and you fit 285/55R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph62.0 mph+2.0 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 265/55R15 or 285/55R15?
285/55R15 is taller by 0.87 inches (27.34" vs 26.48"). 285/55R15 is wider by 0.79 inches.
Can I replace 265/55R15 with 285/55R15?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 285/55R15 change my speedometer?
When your speedometer reads 60 mph with 285/55R15 fitted (calibrated for 265/55R15), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 285/55R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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