Tire Size Box

225/50R15 vs 245/50R15

245/50R15 compared with 225/50R15

+3.3% diameter, +0.8" width

245/50R15 is 24.65" tall vs 23.86". More than the 3% rule of thumb, so check carefully before switching.

23.9"15" rim4.4"8.9" wide
225/50R15 (solid) compared with 245/50R15 (dashed outline), drawn to scale

With 245/50R15 tires, when your speedometer says 60 mph you are really going

62.0 mph

245/50R15 is +0.79 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/50R15245/50R15Difference%
Overall diameter23.86"24.65"+0.79"+3.3%
Section width8.86"9.65"+0.79"+8.9%
Sidewall height4.43"4.82"+0.39"+8.9%
Circumference74.95"77.43"+2.47"+3.3%
Revolutions per mile845.3818.3−27.0−3.2%

Speedometer difference

If your vehicle came with 225/50R15 and you fit 245/50R15, 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 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.5 mph+2.5 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 225/50R15 or 245/50R15?
245/50R15 is taller by 0.79 inches (24.65" vs 23.86"). 245/50R15 is wider by 0.79 inches.
Can I replace 225/50R15 with 245/50R15?
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 245/50R15 change my speedometer?
When your speedometer reads 60 mph with 245/50R15 fitted (calibrated for 225/50R15), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 245/50R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.39 inches of ground clearance at the axle.

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