Tire Size Box

285/40R22 vs 285/45R22

285/45R22 compared with 285/40R22

+3.6% diameter, 0.0" width

285/45R22 is 32.10" tall vs 30.98". More than the 3% rule of thumb, so check carefully before switching.

31.0"22" rim4.5"11.2" wide
285/40R22 (solid) compared with 285/45R22 (dashed outline), drawn to scale

With 285/45R22 tires, when your speedometer says 60 mph you are really going

62.2 mph

285/45R22 is +1.12 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/40R22285/45R22Difference%
Overall diameter30.98"32.10"+1.12"+3.6%
Section width11.22"11.22"0.00"0.0%
Sidewall height4.49"5.05"+0.56"+12.5%
Circumference97.32"100.84"+3.53"+3.6%
Revolutions per mile651.1628.3−22.8−3.5%

Speedometer difference

If your vehicle came with 285/40R22 and you fit 285/45R22, 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 mph62.2 mph+2.2 mph
65 mph67.4 mph+2.4 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 285/40R22 or 285/45R22?
285/45R22 is taller by 1.12 inches (32.10" vs 30.98"). 285/40R22 is the same width.
Can I replace 285/40R22 with 285/45R22?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 285/45R22 change my speedometer?
When your speedometer reads 60 mph with 285/45R22 fitted (calibrated for 285/40R22), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 285/45R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.56 inches of ground clearance at the axle.

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