Tire Size Box

325/30R24 vs 315/35R24

315/35R24 compared with 325/30R24

+3.2% diameter, −0.4" width

315/35R24 is 32.68" tall vs 31.68". More than the 3% rule of thumb, so check carefully before switching.

31.7"24" rim3.8"12.8" wide
325/30R24 (solid) compared with 315/35R24 (dashed outline), drawn to scale

With 315/35R24 tires, when your speedometer says 60 mph you are really going

61.9 mph

315/35R24 is +1.00 inches (+3.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/30R24315/35R24Difference%
Overall diameter31.68"32.68"+1.00"+3.2%
Section width12.80"12.40"−0.39"−3.1%
Sidewall height3.84"4.34"+0.50"+13.1%
Circumference99.52"102.67"+3.15"+3.2%
Revolutions per mile636.7617.1−19.6−3.1%

Speedometer difference

If your vehicle came with 325/30R24 and you fit 315/35R24, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph31.0 mph+1.0 mph
40 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.1 mph+2.1 mph
70 mph72.2 mph+2.2 mph
75 mph77.4 mph+2.4 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 325/30R24 or 315/35R24?
315/35R24 is taller by 1.00 inches (32.68" vs 31.68"). 325/30R24 is wider by 0.39 inches.
Can I replace 325/30R24 with 315/35R24?
It is not recommended without checking carefully. The diameter difference is +3.2%, 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 315/35R24 change my speedometer?
When your speedometer reads 60 mph with 315/35R24 fitted (calibrated for 325/30R24), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.2%.
Will 315/35R24 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

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