Tire Size Box

265/30R22 vs 265/40R22

265/40R22 compared with 265/30R22

+7.4% diameter, 0.0" width

265/40R22 is 30.35" tall vs 28.26". More than the 3% rule of thumb, so check carefully before switching.

28.3"22" rim3.1"10.4" wide
265/30R22 (solid) compared with 265/40R22 (dashed outline), drawn to scale

With 265/40R22 tires, when your speedometer says 60 mph you are really going

64.4 mph

265/40R22 is +2.09 inches (+7.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

265/30R22265/40R22Difference%
Overall diameter28.26"30.35"+2.09"+7.4%
Section width10.43"10.43"0.00"0.0%
Sidewall height3.13"4.17"+1.04"+33.3%
Circumference88.78"95.34"+6.56"+7.4%
Revolutions per mile713.7664.6−49.1−6.9%

Speedometer difference

If your vehicle came with 265/30R22 and you fit 265/40R22, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.5 mph+1.5 mph
30 mph32.2 mph+2.2 mph
40 mph43.0 mph+3.0 mph
50 mph53.7 mph+3.7 mph
60 mph64.4 mph+4.4 mph
65 mph69.8 mph+4.8 mph
70 mph75.2 mph+5.2 mph
75 mph80.5 mph+5.5 mph
80 mph85.9 mph+5.9 mph

Each size on its own

Questions

Which is bigger, 265/30R22 or 265/40R22?
265/40R22 is taller by 2.09 inches (30.35" vs 28.26"). 265/30R22 is the same width.
Can I replace 265/30R22 with 265/40R22?
It is not recommended without checking carefully. The diameter difference is +7.4%, 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 265/40R22 change my speedometer?
When your speedometer reads 60 mph with 265/40R22 fitted (calibrated for 265/30R22), your real speed is 64.4 mph. Your odometer will under-count miles by about 7.4%.
Will 265/40R22 lift my vehicle?
Ride height changes by half the diameter difference: +1.04 inches of ground clearance at the axle.

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