Tire Size Box

255/65R16 vs 275/65R16

275/65R16 compared with 255/65R16

+3.5% diameter, +0.8" width

275/65R16 is 30.07" tall vs 29.05". More than the 3% rule of thumb, so check carefully before switching.

29.1"16" rim6.5"10.0" wide
255/65R16 (solid) compared with 275/65R16 (dashed outline), drawn to scale

With 275/65R16 tires, when your speedometer says 60 mph you are really going

62.1 mph

275/65R16 is +1.02 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

255/65R16275/65R16Difference%
Overall diameter29.05"30.07"+1.02"+3.5%
Section width10.04"10.83"+0.79"+7.8%
Sidewall height6.53"7.04"+0.51"+7.8%
Circumference91.27"94.48"+3.22"+3.5%
Revolutions per mile694.2670.6−23.6−3.4%

Speedometer difference

If your vehicle came with 255/65R16 and you fit 275/65R16, 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 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.1 mph+2.1 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.6 mph+2.6 mph
80 mph82.8 mph+2.8 mph

Each size on its own

Questions

Which is bigger, 255/65R16 or 275/65R16?
275/65R16 is taller by 1.02 inches (30.07" vs 29.05"). 275/65R16 is wider by 0.79 inches.
Can I replace 255/65R16 with 275/65R16?
It is not recommended without checking carefully. The diameter difference is +3.5%, 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 275/65R16 change my speedometer?
When your speedometer reads 60 mph with 275/65R16 fitted (calibrated for 255/65R16), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 275/65R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.51 inches of ground clearance at the axle.

Other comparisons