Tire Size Box

235/45R22 vs 235/55R22

235/55R22 compared with 235/45R22

+6.1% diameter, 0.0" width

235/55R22 is 32.18" tall vs 30.33". More than the 3% rule of thumb, so check carefully before switching.

30.3"22" rim4.2"9.3" wide
235/45R22 (solid) compared with 235/55R22 (dashed outline), drawn to scale

With 235/55R22 tires, when your speedometer says 60 mph you are really going

63.7 mph

235/55R22 is +1.85 inches (+6.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/45R22235/55R22Difference%
Overall diameter30.33"32.18"+1.85"+6.1%
Section width9.25"9.25"0.00"0.0%
Sidewall height4.16"5.09"+0.93"+22.2%
Circumference95.27"101.09"+5.81"+6.1%
Revolutions per mile665.0626.8−38.2−5.8%

Speedometer difference

If your vehicle came with 235/45R22 and you fit 235/55R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.8 mph+1.8 mph
40 mph42.4 mph+2.4 mph
50 mph53.1 mph+3.1 mph
60 mph63.7 mph+3.7 mph
65 mph69.0 mph+4.0 mph
70 mph74.3 mph+4.3 mph
75 mph79.6 mph+4.6 mph
80 mph84.9 mph+4.9 mph

Each size on its own

Questions

Which is bigger, 235/45R22 or 235/55R22?
235/55R22 is taller by 1.85 inches (32.18" vs 30.33"). 235/45R22 is the same width.
Can I replace 235/45R22 with 235/55R22?
It is not recommended without checking carefully. The diameter difference is +6.1%, 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 235/55R22 change my speedometer?
When your speedometer reads 60 mph with 235/55R22 fitted (calibrated for 235/45R22), your real speed is 63.7 mph. Your odometer will under-count miles by about 6.1%.
Will 235/55R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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