Tire Size Box

335/40R19 vs 325/45R19

325/45R19 compared with 335/40R19

+3.3% diameter, −0.4" width

325/45R19 is 30.52" tall vs 29.55". More than the 3% rule of thumb, so check carefully before switching.

29.6"19" rim5.3"13.2" wide
335/40R19 (solid) compared with 325/45R19 (dashed outline), drawn to scale

With 325/45R19 tires, when your speedometer says 60 mph you are really going

62.0 mph

325/45R19 is +0.96 inches (+3.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/40R19325/45R19Difference%
Overall diameter29.55"30.52"+0.96"+3.3%
Section width13.19"12.80"−0.39"−3.0%
Sidewall height5.28"5.76"+0.48"+9.1%
Circumference92.84"95.87"+3.03"+3.3%
Revolutions per mile682.5660.9−21.6−3.2%

Speedometer difference

If your vehicle came with 335/40R19 and you fit 325/45R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph62.0 mph+2.0 mph
65 mph67.1 mph+2.1 mph
70 mph72.3 mph+2.3 mph
75 mph77.4 mph+2.4 mph
80 mph82.6 mph+2.6 mph

Each size on its own

Questions

Which is bigger, 335/40R19 or 325/45R19?
325/45R19 is taller by 0.96 inches (30.52" vs 29.55"). 335/40R19 is wider by 0.39 inches.
Can I replace 335/40R19 with 325/45R19?
It is not recommended without checking carefully. The diameter difference is +3.3%, 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 325/45R19 change my speedometer?
When your speedometer reads 60 mph with 325/45R19 fitted (calibrated for 335/40R19), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.3%.
Will 325/45R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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