Tire Size Box

235/75R16 vs 235/85R16

235/85R16 compared with 235/75R16

+6.2% diameter, 0.0" width

235/85R16 is 31.73" tall vs 29.88". More than the 3% rule of thumb, so check carefully before switching.

29.9"16" rim6.9"9.3" wide
235/75R16 (solid) compared with 235/85R16 (dashed outline), drawn to scale

With 235/85R16 tires, when your speedometer says 60 mph you are really going

63.7 mph

235/85R16 is +1.85 inches (+6.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

235/75R16235/85R16Difference%
Overall diameter29.88"31.73"+1.85"+6.2%
Section width9.25"9.25"0.00"0.0%
Sidewall height6.94"7.86"+0.93"+13.3%
Circumference93.86"99.68"+5.81"+6.2%
Revolutions per mile675.0635.6−39.4−5.8%

Speedometer difference

If your vehicle came with 235/75R16 and you fit 235/85R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.9 mph+1.9 mph
40 mph42.5 mph+2.5 mph
50 mph53.1 mph+3.1 mph
60 mph63.7 mph+3.7 mph
65 mph69.0 mph+4.0 mph
70 mph74.3 mph+4.3 mph
75 mph79.6 mph+4.6 mph
80 mph85.0 mph+5.0 mph

Each size on its own

Questions

Which is bigger, 235/75R16 or 235/85R16?
235/85R16 is taller by 1.85 inches (31.73" vs 29.88"). 235/75R16 is the same width.
Can I replace 235/75R16 with 235/85R16?
It is not recommended without checking carefully. The diameter difference is +6.2%, 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 235/85R16 change my speedometer?
When your speedometer reads 60 mph with 235/85R16 fitted (calibrated for 235/75R16), your real speed is 63.7 mph. Your odometer will under-count miles by about 6.2%.
Will 235/85R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.93 inches of ground clearance at the axle.

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