Tire Size Box

185/75R14 vs 185/85R14

185/85R14 compared with 185/75R14

+5.8% diameter, 0.0" width

185/85R14 is 26.38" tall vs 24.93". More than the 3% rule of thumb, so check carefully before switching.

24.9"14" rim5.5"7.3" wide
185/75R14 (solid) compared with 185/85R14 (dashed outline), drawn to scale

With 185/85R14 tires, when your speedometer says 60 mph you are really going

63.5 mph

185/85R14 is +1.46 inches (+5.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/75R14185/85R14Difference%
Overall diameter24.93"26.38"+1.46"+5.8%
Section width7.28"7.28"0.00"0.0%
Sidewall height5.46"6.19"+0.73"+13.3%
Circumference78.30"82.88"+4.58"+5.8%
Revolutions per mile809.1764.5−44.7−5.5%

Speedometer difference

If your vehicle came with 185/75R14 and you fit 185/85R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.8 mph+1.8 mph
40 mph42.3 mph+2.3 mph
50 mph52.9 mph+2.9 mph
60 mph63.5 mph+3.5 mph
65 mph68.8 mph+3.8 mph
70 mph74.1 mph+4.1 mph
75 mph79.4 mph+4.4 mph
80 mph84.7 mph+4.7 mph

Each size on its own

Questions

Which is bigger, 185/75R14 or 185/85R14?
185/85R14 is taller by 1.46 inches (26.38" vs 24.93"). 185/75R14 is the same width.
Can I replace 185/75R14 with 185/85R14?
It is not recommended without checking carefully. The diameter difference is +5.8%, 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 185/85R14 change my speedometer?
When your speedometer reads 60 mph with 185/85R14 fitted (calibrated for 185/75R14), your real speed is 63.5 mph. Your odometer will under-count miles by about 5.8%.
Will 185/85R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.73 inches of ground clearance at the axle.

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