Tire Size Box

175/75R13 vs 175/85R13

175/85R13 compared with 175/75R13

+5.9% diameter, 0.0" width

175/85R13 is 24.71" tall vs 23.33". More than the 3% rule of thumb, so check carefully before switching.

23.3"13" rim5.2"6.9" wide
175/75R13 (solid) compared with 175/85R13 (dashed outline), drawn to scale

With 175/85R13 tires, when your speedometer says 60 mph you are really going

63.5 mph

175/85R13 is +1.38 inches (+5.9%) in overall diameter. That is more than the 3% most shops and makers recommend.

175/75R13175/85R13Difference%
Overall diameter23.33"24.71"+1.38"+5.9%
Section width6.89"6.89"0.00"0.0%
Sidewall height5.17"5.86"+0.69"+13.3%
Circumference73.31"77.64"+4.33"+5.9%
Revolutions per mile864.3816.1−48.2−5.6%

Speedometer difference

If your vehicle came with 175/75R13 and you fit 175/85R13, 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 mph42.4 mph+2.4 mph
50 mph53.0 mph+3.0 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, 175/75R13 or 175/85R13?
175/85R13 is taller by 1.38 inches (24.71" vs 23.33"). 175/75R13 is the same width.
Can I replace 175/75R13 with 175/85R13?
It is not recommended without checking carefully. The diameter difference is +5.9%, 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 175/85R13 change my speedometer?
When your speedometer reads 60 mph with 175/85R13 fitted (calibrated for 175/75R13), your real speed is 63.5 mph. Your odometer will under-count miles by about 5.9%.
Will 175/85R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.69 inches of ground clearance at the axle.

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