Tire Size Box

255/70R16 vs 275/70R16

275/70R16 compared with 255/70R16

+3.7% diameter, +0.8" width

275/70R16 is 31.16" tall vs 30.06". More than the 3% rule of thumb, so check carefully before switching.

30.1"16" rim7.0"10.0" wide
255/70R16 (solid) compared with 275/70R16 (dashed outline), drawn to scale

With 275/70R16 tires, when your speedometer says 60 mph you are really going

62.2 mph

275/70R16 is +1.10 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/70R16275/70R16Difference%
Overall diameter30.06"31.16"+1.10"+3.7%
Section width10.04"10.83"+0.79"+7.8%
Sidewall height7.03"7.58"+0.55"+7.8%
Circumference94.42"97.88"+3.46"+3.7%
Revolutions per mile671.0647.3−23.7−3.5%

Speedometer difference

If your vehicle came with 255/70R16 and you fit 275/70R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 255/70R16 or 275/70R16?
275/70R16 is taller by 1.10 inches (31.16" vs 30.06"). 275/70R16 is wider by 0.79 inches.
Can I replace 255/70R16 with 275/70R16?
It is not recommended without checking carefully. The diameter difference is +3.7%, 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 275/70R16 change my speedometer?
When your speedometer reads 60 mph with 275/70R16 fitted (calibrated for 255/70R16), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 275/70R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.55 inches of ground clearance at the axle.

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