Tire Size Box

265/75R15 vs 285/75R15

285/75R15 compared with 265/75R15

+3.9% diameter, +0.8" width

285/75R15 is 31.83" tall vs 30.65". More than the 3% rule of thumb, so check carefully before switching.

30.6"15" rim7.8"10.4" wide
265/75R15 (solid) compared with 285/75R15 (dashed outline), drawn to scale

With 285/75R15 tires, when your speedometer says 60 mph you are really going

62.3 mph

285/75R15 is +1.18 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/75R15285/75R15Difference%
Overall diameter30.65"31.83"+1.18"+3.9%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height7.82"8.42"+0.59"+7.5%
Circumference96.29"100.00"+3.71"+3.9%
Revolutions per mile658.0633.6−24.4−3.7%

Speedometer difference

If your vehicle came with 265/75R15 and you fit 285/75R15, 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 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 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, 265/75R15 or 285/75R15?
285/75R15 is taller by 1.18 inches (31.83" vs 30.65"). 285/75R15 is wider by 0.79 inches.
Can I replace 265/75R15 with 285/75R15?
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 285/75R15 change my speedometer?
When your speedometer reads 60 mph with 285/75R15 fitted (calibrated for 265/75R15), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.9%.
Will 285/75R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.59 inches of ground clearance at the axle.

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