Tire Size Box

225/75R14 vs 245/75R14

245/75R14 compared with 225/75R14

+4.3% diameter, +0.8" width

245/75R14 is 28.47" tall vs 27.29". More than the 3% rule of thumb, so check carefully before switching.

27.3"14" rim6.6"8.9" wide
225/75R14 (solid) compared with 245/75R14 (dashed outline), drawn to scale

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

62.6 mph

245/75R14 is +1.18 inches (+4.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/75R14245/75R14Difference%
Overall diameter27.29"28.47"+1.18"+4.3%
Section width8.86"9.65"+0.79"+8.9%
Sidewall height6.64"7.23"+0.59"+8.9%
Circumference85.73"89.44"+3.71"+4.3%
Revolutions per mile739.1708.4−30.7−4.1%

Speedometer difference

If your vehicle came with 225/75R14 and you fit 245/75R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.9 mph+0.9 mph
30 mph31.3 mph+1.3 mph
40 mph41.7 mph+1.7 mph
50 mph52.2 mph+2.2 mph
60 mph62.6 mph+2.6 mph
65 mph67.8 mph+2.8 mph
70 mph73.0 mph+3.0 mph
75 mph78.2 mph+3.2 mph
80 mph83.5 mph+3.5 mph

Each size on its own

Questions

Which is bigger, 225/75R14 or 245/75R14?
245/75R14 is taller by 1.18 inches (28.47" vs 27.29"). 245/75R14 is wider by 0.79 inches.
Can I replace 225/75R14 with 245/75R14?
It is not recommended without checking carefully. The diameter difference is +4.3%, 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 245/75R14 change my speedometer?
When your speedometer reads 60 mph with 245/75R14 fitted (calibrated for 225/75R14), your real speed is 62.6 mph. Your odometer will under-count miles by about 4.3%.
Will 245/75R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.59 inches of ground clearance at the axle.

Other comparisons