Tire Size Box

255/55R15 vs 255/60R15

255/60R15 compared with 255/55R15

+3.9% diameter, 0.0" width

255/60R15 is 27.05" tall vs 26.04". More than the 3% rule of thumb, so check carefully before switching.

26.0"15" rim5.5"10.0" wide
255/55R15 (solid) compared with 255/60R15 (dashed outline), drawn to scale

With 255/60R15 tires, when your speedometer says 60 mph you are really going

62.3 mph

255/60R15 is +1.00 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/55R15255/60R15Difference%
Overall diameter26.04"27.05"+1.00"+3.9%
Section width10.04"10.04"0.00"0.0%
Sidewall height5.52"6.02"+0.50"+9.1%
Circumference81.82"84.97"+3.15"+3.9%
Revolutions per mile774.4745.7−28.7−3.7%

Speedometer difference

If your vehicle came with 255/55R15 and you fit 255/60R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.2 mph+1.2 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 mph
65 mph67.5 mph+2.5 mph
70 mph72.7 mph+2.7 mph
75 mph77.9 mph+2.9 mph
80 mph83.1 mph+3.1 mph

Each size on its own

Questions

Which is bigger, 255/55R15 or 255/60R15?
255/60R15 is taller by 1.00 inches (27.05" vs 26.04"). 255/55R15 is the same width.
Can I replace 255/55R15 with 255/60R15?
It is not recommended without checking carefully. The diameter difference is +3.9%, 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 255/60R15 change my speedometer?
When your speedometer reads 60 mph with 255/60R15 fitted (calibrated for 255/55R15), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.9%.
Will 255/60R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

Other comparisons