Tire Size Box

255/55R16 vs 275/55R16

275/55R16 compared with 255/55R16

+3.2% diameter, +0.8" width

275/55R16 is 27.91" tall vs 27.04". More than the 3% rule of thumb, so check carefully before switching.

27.0"16" rim5.5"10.0" wide
255/55R16 (solid) compared with 275/55R16 (dashed outline), drawn to scale

With 275/55R16 tires, when your speedometer says 60 mph you are really going

61.9 mph

275/55R16 is +0.87 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/55R16275/55R16Difference%
Overall diameter27.04"27.91"+0.87"+3.2%
Section width10.04"10.83"+0.79"+7.8%
Sidewall height5.52"5.95"+0.43"+7.8%
Circumference84.96"87.68"+2.72"+3.2%
Revolutions per mile745.8722.6−23.1−3.1%

Speedometer difference

If your vehicle came with 255/55R16 and you fit 275/55R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.2 mph+2.2 mph
75 mph77.4 mph+2.4 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 255/55R16 or 275/55R16?
275/55R16 is taller by 0.87 inches (27.91" vs 27.04"). 275/55R16 is wider by 0.79 inches.
Can I replace 255/55R16 with 275/55R16?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 275/55R16 change my speedometer?
When your speedometer reads 60 mph with 275/55R16 fitted (calibrated for 255/55R16), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 275/55R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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