Tire Size Box

245/80R16 vs 245/85R16

245/85R16 compared with 245/80R16

+3.1% diameter, 0.0" width

245/85R16 is 32.40" tall vs 31.43". More than the 3% rule of thumb, so check carefully before switching.

31.4"16" rim7.7"9.6" wide
245/80R16 (solid) compared with 245/85R16 (dashed outline), drawn to scale

With 245/85R16 tires, when your speedometer says 60 mph you are really going

61.8 mph

245/85R16 is +0.96 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

245/80R16245/85R16Difference%
Overall diameter31.43"32.40"+0.96"+3.1%
Section width9.65"9.65"0.00"0.0%
Sidewall height7.72"8.20"+0.48"+6.3%
Circumference98.75"101.78"+3.03"+3.1%
Revolutions per mile641.6622.5−19.1−3.0%

Speedometer difference

If your vehicle came with 245/80R16 and you fit 245/85R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 245/80R16 or 245/85R16?
245/85R16 is taller by 0.96 inches (32.40" vs 31.43"). 245/80R16 is the same width.
Can I replace 245/80R16 with 245/85R16?
It is not recommended without checking carefully. The diameter difference is +3.1%, 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 245/85R16 change my speedometer?
When your speedometer reads 60 mph with 245/85R16 fitted (calibrated for 245/80R16), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.1%.
Will 245/85R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.48 inches of ground clearance at the axle.

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