Tire Size Box

335/35R21 vs 335/45R21

335/45R21 compared with 335/35R21

+8.7% diameter, 0.0" width

335/45R21 is 32.87" tall vs 30.23". More than the 3% rule of thumb, so check carefully before switching.

30.2"21" rim4.6"13.2" wide
335/35R21 (solid) compared with 335/45R21 (dashed outline), drawn to scale

With 335/45R21 tires, when your speedometer says 60 mph you are really going

65.2 mph

335/45R21 is +2.64 inches (+8.7%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/35R21335/45R21Difference%
Overall diameter30.23"32.87"+2.64"+8.7%
Section width13.19"13.19"0.00"0.0%
Sidewall height4.62"5.94"+1.32"+28.6%
Circumference94.98"103.26"+8.29"+8.7%
Revolutions per mile667.1613.6−53.5−8.0%

Speedometer difference

If your vehicle came with 335/35R21 and you fit 335/45R21, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.7 mph+1.7 mph
30 mph32.6 mph+2.6 mph
40 mph43.5 mph+3.5 mph
50 mph54.4 mph+4.4 mph
60 mph65.2 mph+5.2 mph
65 mph70.7 mph+5.7 mph
70 mph76.1 mph+6.1 mph
75 mph81.5 mph+6.5 mph
80 mph87.0 mph+7.0 mph

Each size on its own

Questions

Which is bigger, 335/35R21 or 335/45R21?
335/45R21 is taller by 2.64 inches (32.87" vs 30.23"). 335/35R21 is the same width.
Can I replace 335/35R21 with 335/45R21?
It is not recommended without checking carefully. The diameter difference is +8.7%, 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 335/45R21 change my speedometer?
When your speedometer reads 60 mph with 335/45R21 fitted (calibrated for 335/35R21), your real speed is 65.2 mph. Your odometer will under-count miles by about 8.7%.
Will 335/45R21 lift my vehicle?
Ride height changes by half the diameter difference: +1.32 inches of ground clearance at the axle.

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