Tire Size Box

225/50R17 vs 245/50R17

245/50R17 compared with 225/50R17

+3.0% diameter, +0.8" width

245/50R17 is 26.65" tall vs 25.86". More than the 3% rule of thumb, so check carefully before switching.

25.9"17" rim4.4"8.9" wide
225/50R17 (solid) compared with 245/50R17 (dashed outline), drawn to scale

With 245/50R17 tires, when your speedometer says 60 mph you are really going

61.8 mph

245/50R17 is +0.79 inches (+3.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

225/50R17245/50R17Difference%
Overall diameter25.86"26.65"+0.79"+3.0%
Section width8.86"9.65"+0.79"+8.9%
Sidewall height4.43"4.82"+0.39"+8.9%
Circumference81.24"83.71"+2.47"+3.0%
Revolutions per mile779.9756.9−23.0−3.0%

Speedometer difference

If your vehicle came with 225/50R17 and you fit 245/50R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.4 mph+2.4 mph

Each size on its own

Questions

Which is bigger, 225/50R17 or 245/50R17?
245/50R17 is taller by 0.79 inches (26.65" vs 25.86"). 245/50R17 is wider by 0.79 inches.
Can I replace 225/50R17 with 245/50R17?
It is not recommended without checking carefully. The diameter difference is +3.0%, 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 245/50R17 change my speedometer?
When your speedometer reads 60 mph with 245/50R17 fitted (calibrated for 225/50R17), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.0%.
Will 245/50R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.39 inches of ground clearance at the axle.

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