Tire Size Box

335/30R21 vs 335/35R21

335/35R21 compared with 335/30R21

+4.6% diameter, 0.0" width

335/35R21 is 30.23" tall vs 28.91". More than the 3% rule of thumb, so check carefully before switching.

28.9"21" rim4.0"13.2" wide
335/30R21 (solid) compared with 335/35R21 (dashed outline), drawn to scale

With 335/35R21 tires, when your speedometer says 60 mph you are really going

62.7 mph

335/35R21 is +1.32 inches (+4.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/30R21335/35R21Difference%
Overall diameter28.91"30.23"+1.32"+4.6%
Section width13.19"13.19"0.00"0.0%
Sidewall height3.96"4.62"+0.66"+16.7%
Circumference90.83"94.98"+4.14"+4.6%
Revolutions per mile697.5667.1−30.4−4.4%

Speedometer difference

If your vehicle came with 335/30R21 and you fit 335/35R21, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.9 mph+0.9 mph
30 mph31.4 mph+1.4 mph
40 mph41.8 mph+1.8 mph
50 mph52.3 mph+2.3 mph
60 mph62.7 mph+2.7 mph
65 mph68.0 mph+3.0 mph
70 mph73.2 mph+3.2 mph
75 mph78.4 mph+3.4 mph
80 mph83.6 mph+3.6 mph

Each size on its own

Questions

Which is bigger, 335/30R21 or 335/35R21?
335/35R21 is taller by 1.32 inches (30.23" vs 28.91"). 335/30R21 is the same width.
Can I replace 335/30R21 with 335/35R21?
It is not recommended without checking carefully. The diameter difference is +4.6%, 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 335/35R21 change my speedometer?
When your speedometer reads 60 mph with 335/35R21 fitted (calibrated for 335/30R21), your real speed is 62.7 mph. Your odometer will under-count miles by about 4.6%.
Will 335/35R21 lift my vehicle?
Ride height changes by half the diameter difference: +0.66 inches of ground clearance at the axle.

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