Tire Size Box

325/30R19 vs 315/35R19

315/35R19 compared with 325/30R19

+3.8% diameter, −0.4" width

315/35R19 is 27.68" tall vs 26.68". More than the 3% rule of thumb, so check carefully before switching.

26.7"19" rim3.8"12.8" wide
325/30R19 (solid) compared with 315/35R19 (dashed outline), drawn to scale

With 315/35R19 tires, when your speedometer says 60 mph you are really going

62.3 mph

315/35R19 is +1.00 inches (+3.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/30R19315/35R19Difference%
Overall diameter26.68"27.68"+1.00"+3.8%
Section width12.80"12.40"−0.39"−3.1%
Sidewall height3.84"4.34"+0.50"+13.1%
Circumference83.81"86.96"+3.15"+3.8%
Revolutions per mile756.0728.6−27.4−3.6%

Speedometer difference

If your vehicle came with 325/30R19 and you fit 315/35R19, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.8 mph+0.8 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.3 mph+2.3 mph
65 mph67.4 mph+2.4 mph
70 mph72.6 mph+2.6 mph
75 mph77.8 mph+2.8 mph
80 mph83.0 mph+3.0 mph

Each size on its own

Questions

Which is bigger, 325/30R19 or 315/35R19?
315/35R19 is taller by 1.00 inches (27.68" vs 26.68"). 325/30R19 is wider by 0.39 inches.
Can I replace 325/30R19 with 315/35R19?
It is not recommended without checking carefully. The diameter difference is +3.8%, 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 315/35R19 change my speedometer?
When your speedometer reads 60 mph with 315/35R19 fitted (calibrated for 325/30R19), your real speed is 62.3 mph. Your odometer will under-count miles by about 3.8%.
Will 315/35R19 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

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