Tire Size Box

335/30R20 vs 325/35R20

325/35R20 compared with 335/30R20

+3.7% diameter, −0.4" width

325/35R20 is 28.96" tall vs 27.91". More than the 3% rule of thumb, so check carefully before switching.

27.9"20" rim4.0"13.2" wide
335/30R20 (solid) compared with 325/35R20 (dashed outline), drawn to scale

With 325/35R20 tires, when your speedometer says 60 mph you are really going

62.2 mph

325/35R20 is +1.04 inches (+3.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/30R20325/35R20Difference%
Overall diameter27.91"28.96"+1.04"+3.7%
Section width13.19"12.80"−0.39"−3.0%
Sidewall height3.96"4.48"+0.52"+13.2%
Circumference87.69"90.97"+3.28"+3.7%
Revolutions per mile722.5696.5−26.0−3.6%

Speedometer difference

If your vehicle came with 335/30R20 and you fit 325/35R20, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.5 mph+1.5 mph
50 mph51.9 mph+1.9 mph
60 mph62.2 mph+2.2 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, 335/30R20 or 325/35R20?
325/35R20 is taller by 1.04 inches (28.96" vs 27.91"). 335/30R20 is wider by 0.39 inches.
Can I replace 335/30R20 with 325/35R20?
It is not recommended without checking carefully. The diameter difference is +3.7%, 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 325/35R20 change my speedometer?
When your speedometer reads 60 mph with 325/35R20 fitted (calibrated for 335/30R20), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.7%.
Will 325/35R20 lift my vehicle?
Ride height changes by half the diameter difference: +0.52 inches of ground clearance at the axle.

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