Tire Size Box

265/55R17 vs 285/55R17

285/55R17 compared with 265/55R17

+3.0% diameter, +0.8" width

285/55R17 is 29.34" tall vs 28.48". More than the 3% rule of thumb, so check carefully before switching.

28.5"17" rim5.7"10.4" wide
265/55R17 (solid) compared with 285/55R17 (dashed outline), drawn to scale

With 285/55R17 tires, when your speedometer says 60 mph you are really going

61.8 mph

285/55R17 is +0.87 inches (+3.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/55R17285/55R17Difference%
Overall diameter28.48"29.34"+0.87"+3.0%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height5.74"6.17"+0.43"+7.5%
Circumference89.46"92.18"+2.72"+3.0%
Revolutions per mile708.2687.3−20.9−3.0%

Speedometer difference

If your vehicle came with 265/55R17 and you fit 285/55R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.4 mph+2.4 mph

Each size on its own

Questions

Which is bigger, 265/55R17 or 285/55R17?
285/55R17 is taller by 0.87 inches (29.34" vs 28.48"). 285/55R17 is wider by 0.79 inches.
Can I replace 265/55R17 with 285/55R17?
It is not recommended without checking carefully. The diameter difference is +3.0%, 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 285/55R17 change my speedometer?
When your speedometer reads 60 mph with 285/55R17 fitted (calibrated for 265/55R17), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.0%.
Will 285/55R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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