Tire Size Box

255/85R16 vs 275/85R16

275/85R16 compared with 255/85R16

+4.0% diameter, +0.8" width

275/85R16 is 34.41" tall vs 33.07". More than the 3% rule of thumb, so check carefully before switching.

33.1"16" rim8.5"10.0" wide
255/85R16 (solid) compared with 275/85R16 (dashed outline), drawn to scale

With 275/85R16 tires, when your speedometer says 60 mph you are really going

62.4 mph

275/85R16 is +1.34 inches (+4.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/85R16275/85R16Difference%
Overall diameter33.07"34.41"+1.34"+4.0%
Section width10.04"10.83"+0.79"+7.8%
Sidewall height8.53"9.20"+0.67"+7.8%
Circumference103.88"108.09"+4.21"+4.0%
Revolutions per mile609.9586.2−23.7−3.9%

Speedometer difference

If your vehicle came with 255/85R16 and you fit 275/85R16, 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 mph78.0 mph+3.0 mph
80 mph83.2 mph+3.2 mph

Each size on its own

Questions

Which is bigger, 255/85R16 or 275/85R16?
275/85R16 is taller by 1.34 inches (34.41" vs 33.07"). 275/85R16 is wider by 0.79 inches.
Can I replace 255/85R16 with 275/85R16?
It is not recommended without checking carefully. The diameter difference is +4.0%, 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 275/85R16 change my speedometer?
When your speedometer reads 60 mph with 275/85R16 fitted (calibrated for 255/85R16), your real speed is 62.4 mph. Your odometer will under-count miles by about 4.0%.
Will 275/85R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.67 inches of ground clearance at the axle.

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