Tire Size Box

295/40R17 vs 295/45R17

295/45R17 compared with 295/40R17

+4.4% diameter, 0.0" width

295/45R17 is 27.45" tall vs 26.29". More than the 3% rule of thumb, so check carefully before switching.

26.3"17" rim4.6"11.6" wide
295/40R17 (solid) compared with 295/45R17 (dashed outline), drawn to scale

With 295/45R17 tires, when your speedometer says 60 mph you are really going

62.7 mph

295/45R17 is +1.16 inches (+4.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

295/40R17295/45R17Difference%
Overall diameter26.29"27.45"+1.16"+4.4%
Section width11.61"11.61"0.00"0.0%
Sidewall height4.65"5.23"+0.58"+12.5%
Circumference82.60"86.25"+3.65"+4.4%
Revolutions per mile767.1734.6−32.5−4.2%

Speedometer difference

If your vehicle came with 295/40R17 and you fit 295/45R17, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.9 mph+0.9 mph
30 mph31.3 mph+1.3 mph
40 mph41.8 mph+1.8 mph
50 mph52.2 mph+2.2 mph
60 mph62.7 mph+2.7 mph
65 mph67.9 mph+2.9 mph
70 mph73.1 mph+3.1 mph
75 mph78.3 mph+3.3 mph
80 mph83.5 mph+3.5 mph

Each size on its own

Questions

Which is bigger, 295/40R17 or 295/45R17?
295/45R17 is taller by 1.16 inches (27.45" vs 26.29"). 295/40R17 is the same width.
Can I replace 295/40R17 with 295/45R17?
It is not recommended without checking carefully. The diameter difference is +4.4%, 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 295/45R17 change my speedometer?
When your speedometer reads 60 mph with 295/45R17 fitted (calibrated for 295/40R17), your real speed is 62.7 mph. Your odometer will under-count miles by about 4.4%.
Will 295/45R17 lift my vehicle?
Ride height changes by half the diameter difference: +0.58 inches of ground clearance at the axle.

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