Tire Size Box

325/30R22 vs 315/35R22

315/35R22 compared with 325/30R22

+3.4% diameter, −0.4" width

315/35R22 is 30.68" tall vs 29.68". More than the 3% rule of thumb, so check carefully before switching.

29.7"22" rim3.8"12.8" wide
325/30R22 (solid) compared with 315/35R22 (dashed outline), drawn to scale

With 315/35R22 tires, when your speedometer says 60 mph you are really going

62.0 mph

315/35R22 is +1.00 inches (+3.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

325/30R22315/35R22Difference%
Overall diameter29.68"30.68"+1.00"+3.4%
Section width12.80"12.40"−0.39"−3.1%
Sidewall height3.84"4.34"+0.50"+13.1%
Circumference93.23"96.39"+3.15"+3.4%
Revolutions per mile679.6657.3−22.2−3.3%

Speedometer difference

If your vehicle came with 325/30R22 and you fit 315/35R22, 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 mph41.4 mph+1.4 mph
50 mph51.7 mph+1.7 mph
60 mph62.0 mph+2.0 mph
65 mph67.2 mph+2.2 mph
70 mph72.4 mph+2.4 mph
75 mph77.5 mph+2.5 mph
80 mph82.7 mph+2.7 mph

Each size on its own

Questions

Which is bigger, 325/30R22 or 315/35R22?
315/35R22 is taller by 1.00 inches (30.68" vs 29.68"). 325/30R22 is wider by 0.39 inches.
Can I replace 325/30R22 with 315/35R22?
It is not recommended without checking carefully. The diameter difference is +3.4%, 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 315/35R22 change my speedometer?
When your speedometer reads 60 mph with 315/35R22 fitted (calibrated for 325/30R22), your real speed is 62.0 mph. Your odometer will under-count miles by about 3.4%.
Will 315/35R22 lift my vehicle?
Ride height changes by half the diameter difference: +0.50 inches of ground clearance at the axle.

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