Tire Size Box

245/70R14 vs 245/75R14

245/75R14 compared with 245/70R14

+3.5% diameter, 0.0" width

245/75R14 is 28.47" tall vs 27.50". More than the 3% rule of thumb, so check carefully before switching.

27.5"14" rim6.8"9.6" wide
245/70R14 (solid) compared with 245/75R14 (dashed outline), drawn to scale

With 245/75R14 tires, when your speedometer says 60 mph you are really going

62.1 mph

245/75R14 is +0.96 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/70R14245/75R14Difference%
Overall diameter27.50"28.47"+0.96"+3.5%
Section width9.65"9.65"0.00"0.0%
Sidewall height6.75"7.23"+0.48"+7.1%
Circumference86.41"89.44"+3.03"+3.5%
Revolutions per mile733.3708.4−24.8−3.4%

Speedometer difference

If your vehicle came with 245/70R14 and you fit 245/75R14, 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, 245/70R14 or 245/75R14?
245/75R14 is taller by 0.96 inches (28.47" vs 27.50"). 245/70R14 is the same width.
Can I replace 245/70R14 with 245/75R14?
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 245/75R14 change my speedometer?
When your speedometer reads 60 mph with 245/75R14 fitted (calibrated for 245/70R14), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 245/75R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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