Tire Size Box

305/45R22 vs 305/50R22

305/50R22 compared with 305/45R22

+3.7% diameter, 0.0" width

305/50R22 is 34.01" tall vs 32.81". More than the 3% rule of thumb, so check carefully before switching.

32.8"22" rim5.4"12.0" wide
305/45R22 (solid) compared with 305/50R22 (dashed outline), drawn to scale

With 305/50R22 tires, when your speedometer says 60 mph you are really going

62.2 mph

305/50R22 is +1.20 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

305/45R22305/50R22Difference%
Overall diameter32.81"34.01"+1.20"+3.7%
Section width12.01"12.01"0.00"0.0%
Sidewall height5.40"6.00"+0.60"+11.1%
Circumference103.07"106.84"+3.77"+3.7%
Revolutions per mile614.7593.0−21.7−3.5%

Speedometer difference

If your vehicle came with 305/45R22 and you fit 305/50R22, 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 mph41.5 mph+1.5 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 305/45R22 or 305/50R22?
305/50R22 is taller by 1.20 inches (34.01" vs 32.81"). 305/45R22 is the same width.
Can I replace 305/45R22 with 305/50R22?
It is not recommended without checking carefully. The diameter difference is +3.7%, 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 305/50R22 change my speedometer?
When your speedometer reads 60 mph with 305/50R22 fitted (calibrated for 305/45R22), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 305/50R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.60 inches of ground clearance at the axle.

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