335/35R24 vs 325/40R24

325/40R24 compared with 335/35R24

+3.0% diameter, −0.4" width

325/40R24 is 34.24" tall vs 33.23". More than the 3% rule of thumb, so check carefully before switching.

33.2"24" rim4.6"13.2" wide
335/35R24 (solid) compared with 325/40R24 (dashed outline), drawn to scale

With 325/40R24 tires, when your speedometer says 60 mph you are really going

61.8 mph

325/40R24 is +1.00 inches (+3.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/35R24325/40R24Difference%
Overall diameter33.23"34.24"+1.00"+3.0%
Section width13.19"12.80"−0.39"−3.0%
Sidewall height4.62"5.12"+0.50"+10.9%
Circumference104.40"107.56"+3.15"+3.0%
Revolutions per mile606.9589.1−17.8−2.9%

Speedometer difference

If your vehicle came with 335/35R24 and you fit 325/40R24, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.4 mph+2.4 mph

Each size on its own

Questions

Which is bigger, 335/35R24 or 325/40R24?
325/40R24 is taller by 1.00 inches (34.24" vs 33.23"). 335/35R24 is wider by 0.39 inches.
Can I replace 335/35R24 with 325/40R24?
It is not recommended without checking carefully. The diameter difference is +3.0%, 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 325/40R24 change my speedometer?
When your speedometer reads 60 mph with 325/40R24 fitted (calibrated for 335/35R24), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.0%.
Will 325/40R24 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

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