Tire Size Box

285/40R16 vs 285/50R16

285/50R16 compared with 285/40R16

+9.0% diameter, 0.0" width

285/50R16 is 27.22" tall vs 24.98". More than the 3% rule of thumb, so check carefully before switching.

25.0"16" rim4.5"11.2" wide
285/40R16 (solid) compared with 285/50R16 (dashed outline), drawn to scale

With 285/50R16 tires, when your speedometer says 60 mph you are really going

65.4 mph

285/50R16 is +2.24 inches (+9.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/40R16285/50R16Difference%
Overall diameter24.98"27.22"+2.24"+9.0%
Section width11.22"11.22"0.00"0.0%
Sidewall height4.49"5.61"+1.12"+25.0%
Circumference78.47"85.52"+7.05"+9.0%
Revolutions per mile807.5740.9−66.6−8.2%

Speedometer difference

If your vehicle came with 285/40R16 and you fit 285/50R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.8 mph+1.8 mph
30 mph32.7 mph+2.7 mph
40 mph43.6 mph+3.6 mph
50 mph54.5 mph+4.5 mph
60 mph65.4 mph+5.4 mph
65 mph70.8 mph+5.8 mph
70 mph76.3 mph+6.3 mph
75 mph81.7 mph+6.7 mph
80 mph87.2 mph+7.2 mph

Each size on its own

Questions

Which is bigger, 285/40R16 or 285/50R16?
285/50R16 is taller by 2.24 inches (27.22" vs 24.98"). 285/40R16 is the same width.
Can I replace 285/40R16 with 285/50R16?
It is not recommended without checking carefully. The diameter difference is +9.0%, 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 285/50R16 change my speedometer?
When your speedometer reads 60 mph with 285/50R16 fitted (calibrated for 285/40R16), your real speed is 65.4 mph. Your odometer will under-count miles by about 9.0%.
Will 285/50R16 lift my vehicle?
Ride height changes by half the diameter difference: +1.12 inches of ground clearance at the axle.

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