Tire Size Box

235/60R14 vs 255/60R14

255/60R14 compared with 235/60R14

+3.8% diameter, +0.8" width

255/60R14 is 26.05" tall vs 25.10". More than the 3% rule of thumb, so check carefully before switching.

25.1"14" rim5.6"9.3" wide
235/60R14 (solid) compared with 255/60R14 (dashed outline), drawn to scale

With 255/60R14 tires, when your speedometer says 60 mph you are really going

62.3 mph

255/60R14 is +0.94 inches (+3.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/60R14255/60R14Difference%
Overall diameter25.10"26.05"+0.94"+3.8%
Section width9.25"10.04"+0.79"+8.5%
Sidewall height5.55"6.02"+0.47"+8.5%
Circumference78.86"81.83"+2.97"+3.8%
Revolutions per mile803.4774.3−29.1−3.6%

Speedometer difference

If your vehicle came with 235/60R14 and you fit 255/60R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph83.0 mph+3.0 mph

Each size on its own

Questions

Which is bigger, 235/60R14 or 255/60R14?
255/60R14 is taller by 0.94 inches (26.05" vs 25.10"). 255/60R14 is wider by 0.79 inches.
Can I replace 235/60R14 with 255/60R14?
It is not recommended without checking carefully. The diameter difference is +3.8%, 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 255/60R14 change my speedometer?
When your speedometer reads 60 mph with 255/60R14 fitted (calibrated for 235/60R14), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.8%.
Will 255/60R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.47 inches of ground clearance at the axle.

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