Tire Size Box

265/60R18 vs 285/60R18

285/60R18 compared with 265/60R18

+3.1% diameter, +0.8" width

285/60R18 is 31.46" tall vs 30.52". More than the 3% rule of thumb, so check carefully before switching.

30.5"18" rim6.3"10.4" wide
265/60R18 (solid) compared with 285/60R18 (dashed outline), drawn to scale

With 285/60R18 tires, when your speedometer says 60 mph you are really going

61.9 mph

285/60R18 is +0.94 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/60R18285/60R18Difference%
Overall diameter30.52"31.46"+0.94"+3.1%
Section width10.43"11.22"+0.79"+7.5%
Sidewall height6.26"6.73"+0.47"+7.5%
Circumference95.88"98.85"+2.97"+3.1%
Revolutions per mile660.8641.0−19.8−3.0%

Speedometer difference

If your vehicle came with 265/60R18 and you fit 285/60R18, 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 mph61.9 mph+1.9 mph
65 mph67.0 mph+2.0 mph
70 mph72.2 mph+2.2 mph
75 mph77.3 mph+2.3 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 265/60R18 or 285/60R18?
285/60R18 is taller by 0.94 inches (31.46" vs 30.52"). 285/60R18 is wider by 0.79 inches.
Can I replace 265/60R18 with 285/60R18?
It is not recommended without checking carefully. The diameter difference is +3.1%, 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 285/60R18 change my speedometer?
When your speedometer reads 60 mph with 285/60R18 fitted (calibrated for 265/60R18), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.1%.
Will 285/60R18 lift my vehicle?
Ride height changes by half the diameter difference: +0.47 inches of ground clearance at the axle.

Other comparisons