Tire Size Box

235/75R14 vs 235/80R14

235/80R14 compared with 235/75R14

+3.3% diameter, 0.0" width

235/80R14 is 28.80" tall vs 27.88". More than the 3% rule of thumb, so check carefully before switching.

27.9"14" rim6.9"9.3" wide
235/75R14 (solid) compared with 235/80R14 (dashed outline), drawn to scale

With 235/80R14 tires, when your speedometer says 60 mph you are really going

62.0 mph

235/80R14 is +0.93 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/75R14235/80R14Difference%
Overall diameter27.88"28.80"+0.93"+3.3%
Section width9.25"9.25"0.00"0.0%
Sidewall height6.94"7.40"+0.46"+6.7%
Circumference87.58"90.49"+2.91"+3.3%
Revolutions per mile723.4700.2−23.2−3.2%

Speedometer difference

If your vehicle came with 235/75R14 and you fit 235/80R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 235/75R14 or 235/80R14?
235/80R14 is taller by 0.93 inches (28.80" vs 27.88"). 235/75R14 is the same width.
Can I replace 235/75R14 with 235/80R14?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 235/80R14 change my speedometer?
When your speedometer reads 60 mph with 235/80R14 fitted (calibrated for 235/75R14), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 235/80R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.46 inches of ground clearance at the axle.

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