Tire Size Box

325/45R22 vs 325/50R22

325/50R22 compared with 325/45R22

+3.8% diameter, 0.0" width

325/50R22 is 34.80" tall vs 33.52". More than the 3% rule of thumb, so check carefully before switching.

33.5"22" rim5.8"12.8" wide
325/45R22 (solid) compared with 325/50R22 (dashed outline), drawn to scale

With 325/50R22 tires, when your speedometer says 60 mph you are really going

62.3 mph

325/50R22 is +1.28 inches (+3.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/45R22325/50R22Difference%
Overall diameter33.52"34.80"+1.28"+3.8%
Section width12.80"12.80"0.00"0.0%
Sidewall height5.76"6.40"+0.64"+11.1%
Circumference105.29"109.31"+4.02"+3.8%
Revolutions per mile601.8579.6−22.1−3.7%

Speedometer difference

If your vehicle came with 325/45R22 and you fit 325/50R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 mph
65 mph67.5 mph+2.5 mph
70 mph72.7 mph+2.7 mph
75 mph77.9 mph+2.9 mph
80 mph83.1 mph+3.1 mph

Each size on its own

Questions

Which is bigger, 325/45R22 or 325/50R22?
325/50R22 is taller by 1.28 inches (34.80" vs 33.52"). 325/45R22 is the same width.
Can I replace 325/45R22 with 325/50R22?
It is not recommended without checking carefully. The diameter difference is +3.8%, 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 325/50R22 change my speedometer?
When your speedometer reads 60 mph with 325/50R22 fitted (calibrated for 325/45R22), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.8%.
Will 325/50R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.64 inches of ground clearance at the axle.

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