Tire Size Box

245/75R14 vs 245/80R14

245/80R14 compared with 245/75R14

+3.4% diameter, 0.0" width

245/80R14 is 29.43" tall vs 28.47". More than the 3% rule of thumb, so check carefully before switching.

28.5"14" rim7.2"9.6" wide
245/75R14 (solid) compared with 245/80R14 (dashed outline), drawn to scale

With 245/80R14 tires, when your speedometer says 60 mph you are really going

62.0 mph

245/80R14 is +0.96 inches (+3.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/75R14245/80R14Difference%
Overall diameter28.47"29.43"+0.96"+3.4%
Section width9.65"9.65"0.00"0.0%
Sidewall height7.23"7.72"+0.48"+6.7%
Circumference89.44"92.47"+3.03"+3.4%
Revolutions per mile708.4685.2−23.2−3.3%

Speedometer difference

If your vehicle came with 245/75R14 and you fit 245/80R14, 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 mph41.4 mph+1.4 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.4 mph+2.4 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 245/75R14 or 245/80R14?
245/80R14 is taller by 0.96 inches (29.43" vs 28.47"). 245/75R14 is the same width.
Can I replace 245/75R14 with 245/80R14?
It is not recommended without checking carefully. The diameter difference is +3.4%, 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 245/80R14 change my speedometer?
When your speedometer reads 60 mph with 245/80R14 fitted (calibrated for 245/75R14), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.4%.
Will 245/80R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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