Tire Size Box

325/35R19 vs 325/45R19

325/45R19 compared with 325/35R19

+9.2% diameter, 0.0" width

325/45R19 is 30.52" tall vs 27.96". More than the 3% rule of thumb, so check carefully before switching.

28.0"19" rim4.5"12.8" wide
325/35R19 (solid) compared with 325/45R19 (dashed outline), drawn to scale

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

65.5 mph

325/45R19 is +2.56 inches (+9.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/35R19325/45R19Difference%
Overall diameter27.96"30.52"+2.56"+9.2%
Section width12.80"12.80"0.00"0.0%
Sidewall height4.48"5.76"+1.28"+28.6%
Circumference87.83"95.87"+8.04"+9.2%
Revolutions per mile721.4660.9−60.5−8.4%

Speedometer difference

If your vehicle came with 325/35R19 and you fit 325/45R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.8 mph+1.8 mph
30 mph32.7 mph+2.7 mph
40 mph43.7 mph+3.7 mph
50 mph54.6 mph+4.6 mph
60 mph65.5 mph+5.5 mph
65 mph70.9 mph+5.9 mph
70 mph76.4 mph+6.4 mph
75 mph81.9 mph+6.9 mph
80 mph87.3 mph+7.3 mph

Each size on its own

Questions

Which is bigger, 325/35R19 or 325/45R19?
325/45R19 is taller by 2.56 inches (30.52" vs 27.96"). 325/35R19 is the same width.
Can I replace 325/35R19 with 325/45R19?
It is not recommended without checking carefully. The diameter difference is +9.2%, 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 325/35R19), your real speed is 65.5 mph. Your odometer will under-count miles by about 9.2%.
Will 325/45R19 lift my vehicle?
Ride height changes by half the diameter difference: +1.28 inches of ground clearance at the axle.

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