Tire Size Box

205/45R15 vs 225/45R15

225/45R15 compared with 205/45R15

+3.2% diameter, +0.8" width

225/45R15 is 22.97" tall vs 22.26". More than the 3% rule of thumb, so check carefully before switching.

22.3"15" rim3.6"8.1" wide
205/45R15 (solid) compared with 225/45R15 (dashed outline), drawn to scale

With 225/45R15 tires, when your speedometer says 60 mph you are really going

61.9 mph

225/45R15 is +0.71 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

205/45R15225/45R15Difference%
Overall diameter22.26"22.97"+0.71"+3.2%
Section width8.07"8.86"+0.79"+9.8%
Sidewall height3.63"3.99"+0.35"+9.8%
Circumference69.94"72.17"+2.23"+3.2%
Revolutions per mile905.9877.9−27.9−3.1%

Speedometer difference

If your vehicle came with 205/45R15 and you fit 225/45R15, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.2 mph+2.2 mph
75 mph77.4 mph+2.4 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 205/45R15 or 225/45R15?
225/45R15 is taller by 0.71 inches (22.97" vs 22.26"). 225/45R15 is wider by 0.79 inches.
Can I replace 205/45R15 with 225/45R15?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 225/45R15 change my speedometer?
When your speedometer reads 60 mph with 225/45R15 fitted (calibrated for 205/45R15), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 225/45R15 lift my vehicle?
Ride height changes by half the diameter difference: +0.35 inches of ground clearance at the axle.

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