Tire Size Box

285/60R20 vs 285/65R20

285/65R20 compared with 285/60R20

+3.4% diameter, 0.0" width

285/65R20 is 34.59" tall vs 33.46". More than the 3% rule of thumb, so check carefully before switching.

33.5"20" rim6.7"11.2" wide
285/60R20 (solid) compared with 285/65R20 (dashed outline), drawn to scale

With 285/65R20 tires, when your speedometer says 60 mph you are really going

62.0 mph

285/65R20 is +1.12 inches (+3.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/60R20285/65R20Difference%
Overall diameter33.46"34.59"+1.12"+3.4%
Section width11.22"11.22"0.00"0.0%
Sidewall height6.73"7.29"+0.56"+8.3%
Circumference105.13"108.66"+3.53"+3.4%
Revolutions per mile602.7583.1−19.6−3.2%

Speedometer difference

If your vehicle came with 285/60R20 and you fit 285/65R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 285/60R20 or 285/65R20?
285/65R20 is taller by 1.12 inches (34.59" vs 33.46"). 285/60R20 is the same width.
Can I replace 285/60R20 with 285/65R20?
It is not recommended without checking carefully. The diameter difference is +3.4%, 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 285/65R20 change my speedometer?
When your speedometer reads 60 mph with 285/65R20 fitted (calibrated for 285/60R20), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.4%.
Will 285/65R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.56 inches of ground clearance at the axle.

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