Tire Size Box

305/50R22 vs 305/55R22

305/55R22 compared with 305/50R22

+3.5% diameter, 0.0" width

305/55R22 is 35.21" tall vs 34.01". More than the 3% rule of thumb, so check carefully before switching.

34.0"22" rim6.0"12.0" wide
305/50R22 (solid) compared with 305/55R22 (dashed outline), drawn to scale

With 305/55R22 tires, when your speedometer says 60 mph you are really going

62.1 mph

305/55R22 is +1.20 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

305/50R22305/55R22Difference%
Overall diameter34.01"35.21"+1.20"+3.5%
Section width12.01"12.01"0.00"0.0%
Sidewall height6.00"6.60"+0.60"+10.0%
Circumference106.84"110.61"+3.77"+3.5%
Revolutions per mile593.0572.8−20.2−3.4%

Speedometer difference

If your vehicle came with 305/50R22 and you fit 305/55R22, 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 mph77.6 mph+2.6 mph
80 mph82.8 mph+2.8 mph

Each size on its own

Questions

Which is bigger, 305/50R22 or 305/55R22?
305/55R22 is taller by 1.20 inches (35.21" vs 34.01"). 305/50R22 is the same width.
Can I replace 305/50R22 with 305/55R22?
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 305/55R22 change my speedometer?
When your speedometer reads 60 mph with 305/55R22 fitted (calibrated for 305/50R22), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 305/55R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.60 inches of ground clearance at the axle.

Other comparisons