Tire Size Box

235/75R16 vs 255/75R16

255/75R16 compared with 235/75R16

+4.0% diameter, +0.8" width

255/75R16 is 31.06" tall vs 29.88". More than the 3% rule of thumb, so check carefully before switching.

29.9"16" rim6.9"9.3" wide
235/75R16 (solid) compared with 255/75R16 (dashed outline), drawn to scale

With 255/75R16 tires, when your speedometer says 60 mph you are really going

62.4 mph

255/75R16 is +1.18 inches (+4.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/75R16255/75R16Difference%
Overall diameter29.88"31.06"+1.18"+4.0%
Section width9.25"10.04"+0.79"+8.5%
Sidewall height6.94"7.53"+0.59"+8.5%
Circumference93.86"97.57"+3.71"+4.0%
Revolutions per mile675.0649.3−25.7−3.8%

Speedometer difference

If your vehicle came with 235/75R16 and you fit 255/75R16, 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, 235/75R16 or 255/75R16?
255/75R16 is taller by 1.18 inches (31.06" vs 29.88"). 255/75R16 is wider by 0.79 inches.
Can I replace 235/75R16 with 255/75R16?
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 255/75R16 change my speedometer?
When your speedometer reads 60 mph with 255/75R16 fitted (calibrated for 235/75R16), your real speed is 62.4 mph. Your odometer will under-count miles by about 4.0%.
Will 255/75R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.59 inches of ground clearance at the axle.

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