Tire Size Box

225/55R14 vs 245/55R14

245/55R14 compared with 225/55R14

+3.6% diameter, +0.8" width

245/55R14 is 24.61" tall vs 23.74". More than the 3% rule of thumb, so check carefully before switching.

23.7"14" rim4.9"8.9" wide
225/55R14 (solid) compared with 245/55R14 (dashed outline), drawn to scale

With 245/55R14 tires, when your speedometer says 60 mph you are really going

62.2 mph

245/55R14 is +0.87 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/55R14245/55R14Difference%
Overall diameter23.74"24.61"+0.87"+3.6%
Section width8.86"9.65"+0.79"+8.9%
Sidewall height4.87"5.31"+0.43"+8.9%
Circumference74.59"77.32"+2.72"+3.6%
Revolutions per mile849.4819.5−29.9−3.5%

Speedometer difference

If your vehicle came with 225/55R14 and you fit 245/55R14, 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 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 225/55R14 or 245/55R14?
245/55R14 is taller by 0.87 inches (24.61" vs 23.74"). 245/55R14 is wider by 0.79 inches.
Can I replace 225/55R14 with 245/55R14?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 245/55R14 change my speedometer?
When your speedometer reads 60 mph with 245/55R14 fitted (calibrated for 225/55R14), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 245/55R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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