Tire Size Box

285/70R16 vs 285/80R16

285/80R16 compared with 285/70R16

+7.1% diameter, 0.0" width

285/80R16 is 33.95" tall vs 31.71". More than the 3% rule of thumb, so check carefully before switching.

31.7"16" rim7.9"11.2" wide
285/70R16 (solid) compared with 285/80R16 (dashed outline), drawn to scale

With 285/80R16 tires, when your speedometer says 60 mph you are really going

64.2 mph

285/80R16 is +2.24 inches (+7.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

285/70R16285/80R16Difference%
Overall diameter31.71"33.95"+2.24"+7.1%
Section width11.22"11.22"0.00"0.0%
Sidewall height7.85"8.98"+1.12"+14.3%
Circumference99.62"106.67"+7.05"+7.1%
Revolutions per mile636.0594.0−42.0−6.6%

Speedometer difference

If your vehicle came with 285/70R16 and you fit 285/80R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.4 mph+1.4 mph
30 mph32.1 mph+2.1 mph
40 mph42.8 mph+2.8 mph
50 mph53.5 mph+3.5 mph
60 mph64.2 mph+4.2 mph
65 mph69.6 mph+4.6 mph
70 mph75.0 mph+5.0 mph
75 mph80.3 mph+5.3 mph
80 mph85.7 mph+5.7 mph

Each size on its own

Questions

Which is bigger, 285/70R16 or 285/80R16?
285/80R16 is taller by 2.24 inches (33.95" vs 31.71"). 285/70R16 is the same width.
Can I replace 285/70R16 with 285/80R16?
It is not recommended without checking carefully. The diameter difference is +7.1%, 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 285/80R16 change my speedometer?
When your speedometer reads 60 mph with 285/80R16 fitted (calibrated for 285/70R16), your real speed is 64.2 mph. Your odometer will under-count miles by about 7.1%.
Will 285/80R16 lift my vehicle?
Ride height changes by half the diameter difference: +1.12 inches of ground clearance at the axle.

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