Tire Size Box

265/80R15 vs 285/80R15

285/80R15 compared with 265/80R15

+4.0% diameter, +0.8" width

285/80R15 is 32.95" tall vs 31.69". More than the 3% rule of thumb, so check carefully before switching.

31.7"15" rim8.3"10.4" wide
265/80R15 (solid) compared with 285/80R15 (dashed outline), drawn to scale

With 285/80R15 tires, when your speedometer says 60 mph you are really going

62.4 mph

285/80R15 is +1.26 inches (+4.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/80R15285/80R15Difference%
Overall diameter31.69"32.95"+1.26"+4.0%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height8.35"8.98"+0.63"+7.5%
Circumference99.57"103.52"+3.96"+4.0%
Revolutions per mile636.4612.0−24.3−3.8%

Speedometer difference

If your vehicle came with 265/80R15 and you fit 285/80R15, 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, 265/80R15 or 285/80R15?
285/80R15 is taller by 1.26 inches (32.95" vs 31.69"). 285/80R15 is wider by 0.79 inches.
Can I replace 265/80R15 with 285/80R15?
It is not recommended without checking carefully. The diameter difference is +4.0%, 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 285/80R15 change my speedometer?
When your speedometer reads 60 mph with 285/80R15 fitted (calibrated for 265/80R15), your real speed is 62.4 mph. Your odometer will under-count miles by about 4.0%.
Will 285/80R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.63 inches of ground clearance at the axle.

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