Tire Size Box

335/40R20 vs 335/50R20

335/50R20 compared with 335/40R20

+8.6% diameter, 0.0" width

335/50R20 is 33.19" tall vs 30.55". More than the 3% rule of thumb, so check carefully before switching.

30.6"20" rim5.3"13.2" wide
335/40R20 (solid) compared with 335/50R20 (dashed outline), drawn to scale

With 335/50R20 tires, when your speedometer says 60 mph you are really going

65.2 mph

335/50R20 is +2.64 inches (+8.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

335/40R20335/50R20Difference%
Overall diameter30.55"33.19"+2.64"+8.6%
Section width13.19"13.19"0.00"0.0%
Sidewall height5.28"6.59"+1.32"+25.0%
Circumference95.98"104.27"+8.29"+8.6%
Revolutions per mile660.1607.7−52.5−7.9%

Speedometer difference

If your vehicle came with 335/40R20 and you fit 335/50R20, 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 mph54.3 mph+4.3 mph
60 mph65.2 mph+5.2 mph
65 mph70.6 mph+5.6 mph
70 mph76.0 mph+6.0 mph
75 mph81.5 mph+6.5 mph
80 mph86.9 mph+6.9 mph

Each size on its own

Questions

Which is bigger, 335/40R20 or 335/50R20?
335/50R20 is taller by 2.64 inches (33.19" vs 30.55"). 335/40R20 is the same width.
Can I replace 335/40R20 with 335/50R20?
It is not recommended without checking carefully. The diameter difference is +8.6%, 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 335/50R20 change my speedometer?
When your speedometer reads 60 mph with 335/50R20 fitted (calibrated for 335/40R20), your real speed is 65.2 mph. Your odometer will under-count miles by about 8.6%.
Will 335/50R20 lift my vehicle?
Ride height changes by half the diameter difference: +1.32 inches of ground clearance at the axle.

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