Tire Size Box

225/45R17 vs 225/50R17

225/50R17 compared with 225/45R17

+3.5% diameter, 0.0" width

225/50R17 is 25.86" tall vs 24.97". More than the 3% rule of thumb, so check carefully before switching.

25.0"17" rim4.0"8.9" wide
225/45R17 (solid) compared with 225/50R17 (dashed outline), drawn to scale

With 225/50R17 tires, when your speedometer says 60 mph you are really going

62.1 mph

225/50R17 is +0.89 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/45R17225/50R17Difference%
Overall diameter24.97"25.86"+0.89"+3.5%
Section width8.86"8.86"0.00"0.0%
Sidewall height3.99"4.43"+0.44"+11.1%
Circumference78.45"81.24"+2.78"+3.5%
Revolutions per mile807.6779.9−27.7−3.4%

Speedometer difference

If your vehicle came with 225/45R17 and you fit 225/50R17, 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 mph77.7 mph+2.7 mph
80 mph82.8 mph+2.8 mph

Each size on its own

Questions

Which is bigger, 225/45R17 or 225/50R17?
225/50R17 is taller by 0.89 inches (25.86" vs 24.97"). 225/45R17 is the same width.
Can I replace 225/45R17 with 225/50R17?
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 225/50R17 change my speedometer?
When your speedometer reads 60 mph with 225/50R17 fitted (calibrated for 225/45R17), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 225/50R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.44 inches of ground clearance at the axle.

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