Tire Size Box

275/40R22 vs 275/45R22

275/45R22 compared with 275/40R22

+3.5% diameter, 0.0" width

275/45R22 is 31.74" tall vs 30.66". More than the 3% rule of thumb, so check carefully before switching.

30.7"22" rim4.3"10.8" wide
275/40R22 (solid) compared with 275/45R22 (dashed outline), drawn to scale

With 275/45R22 tires, when your speedometer says 60 mph you are really going

62.1 mph

275/45R22 is +1.08 inches (+3.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

275/40R22275/45R22Difference%
Overall diameter30.66"31.74"+1.08"+3.5%
Section width10.83"10.83"0.00"0.0%
Sidewall height4.33"4.87"+0.54"+12.5%
Circumference96.33"99.73"+3.40"+3.5%
Revolutions per mile657.8635.3−22.4−3.4%

Speedometer difference

If your vehicle came with 275/40R22 and you fit 275/45R22, 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 mph62.1 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, 275/40R22 or 275/45R22?
275/45R22 is taller by 1.08 inches (31.74" vs 30.66"). 275/40R22 is the same width.
Can I replace 275/40R22 with 275/45R22?
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 275/45R22 change my speedometer?
When your speedometer reads 60 mph with 275/45R22 fitted (calibrated for 275/40R22), your real speed is 62.1 mph. Your odometer will under-count miles by about 3.5%.
Will 275/45R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.54 inches of ground clearance at the axle.

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