Tire Size Box

265/70R15 vs 285/70R15

285/70R15 compared with 265/70R15

+3.7% diameter, +0.8" width

285/70R15 is 30.71" tall vs 29.61". More than the 3% rule of thumb, so check carefully before switching.

29.6"15" rim7.3"10.4" wide
265/70R15 (solid) compared with 285/70R15 (dashed outline), drawn to scale

With 285/70R15 tires, when your speedometer says 60 mph you are really going

62.2 mph

285/70R15 is +1.10 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/70R15285/70R15Difference%
Overall diameter29.61"30.71"+1.10"+3.7%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height7.30"7.85"+0.55"+7.5%
Circumference93.01"96.47"+3.46"+3.7%
Revolutions per mile681.2656.8−24.5−3.6%

Speedometer difference

If your vehicle came with 265/70R15 and you fit 285/70R15, 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 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph83.0 mph+3.0 mph

Each size on its own

Questions

Which is bigger, 265/70R15 or 285/70R15?
285/70R15 is taller by 1.10 inches (30.71" vs 29.61"). 285/70R15 is wider by 0.79 inches.
Can I replace 265/70R15 with 285/70R15?
It is not recommended without checking carefully. The diameter difference is +3.7%, 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 285/70R15 change my speedometer?
When your speedometer reads 60 mph with 285/70R15 fitted (calibrated for 265/70R15), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 285/70R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.55 inches of ground clearance at the axle.

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