Tire Size Box

275/55R20 vs 275/60R20

275/60R20 compared with 275/55R20

+3.4% diameter, 0.0" width

275/60R20 is 32.99" tall vs 31.91". More than the 3% rule of thumb, so check carefully before switching.

31.9"20" rim6.0"10.8" wide
275/55R20 (solid) compared with 275/60R20 (dashed outline), drawn to scale

With 275/60R20 tires, when your speedometer says 60 mph you are really going

62.0 mph

275/60R20 is +1.08 inches (+3.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/55R20275/60R20Difference%
Overall diameter31.91"32.99"+1.08"+3.4%
Section width10.83"10.83"0.00"0.0%
Sidewall height5.95"6.50"+0.54"+9.1%
Circumference100.25"103.65"+3.40"+3.4%
Revolutions per mile632.0611.3−20.7−3.3%

Speedometer difference

If your vehicle came with 275/55R20 and you fit 275/60R20, 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 mph41.4 mph+1.4 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.4 mph+2.4 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 275/55R20 or 275/60R20?
275/60R20 is taller by 1.08 inches (32.99" vs 31.91"). 275/55R20 is the same width.
Can I replace 275/55R20 with 275/60R20?
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 275/60R20 change my speedometer?
When your speedometer reads 60 mph with 275/60R20 fitted (calibrated for 275/55R20), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.4%.
Will 275/60R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.54 inches of ground clearance at the axle.

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