Tire Size Box

255/80R16 vs 275/80R16

275/80R16 compared with 255/80R16

+3.9% diameter, +0.8" width

275/80R16 is 33.32" tall vs 32.06". More than the 3% rule of thumb, so check carefully before switching.

32.1"16" rim8.0"10.0" wide
255/80R16 (solid) compared with 275/80R16 (dashed outline), drawn to scale

With 275/80R16 tires, when your speedometer says 60 mph you are really going

62.4 mph

275/80R16 is +1.26 inches (+3.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/80R16275/80R16Difference%
Overall diameter32.06"33.32"+1.26"+3.9%
Section width10.04"10.83"+0.79"+7.8%
Sidewall height8.03"8.66"+0.63"+7.8%
Circumference100.73"104.69"+3.96"+3.9%
Revolutions per mile629.0605.2−23.8−3.8%

Speedometer difference

If your vehicle came with 255/80R16 and you fit 275/80R16, 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 mph41.6 mph+1.6 mph
50 mph52.0 mph+2.0 mph
60 mph62.4 mph+2.4 mph
65 mph67.6 mph+2.6 mph
70 mph72.8 mph+2.8 mph
75 mph77.9 mph+2.9 mph
80 mph83.1 mph+3.1 mph

Each size on its own

Questions

Which is bigger, 255/80R16 or 275/80R16?
275/80R16 is taller by 1.26 inches (33.32" vs 32.06"). 275/80R16 is wider by 0.79 inches.
Can I replace 255/80R16 with 275/80R16?
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 275/80R16 change my speedometer?
When your speedometer reads 60 mph with 275/80R16 fitted (calibrated for 255/80R16), your real speed is 62.4 mph. Your odometer will under-count miles by about 3.9%.
Will 275/80R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.63 inches of ground clearance at the axle.

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