Tire Size Box

175/80R13 vs 165/85R13

165/85R13 compared with 175/80R13

+0.1% diameter, −0.4" width

165/85R13 is 24.04" tall vs 24.02". Within the 3% rule, so usually interchangeable.

24.0"13" rim5.5"6.9" wide
175/80R13 (solid) compared with 165/85R13 (dashed outline), drawn to scale

With 165/85R13 tires, when your speedometer says 60 mph you are really going

60.0 mph

165/85R13 is +0.02 inches (+0.1%) in overall diameter. That is within the 3% most shops and makers allow.

175/80R13165/85R13Difference%
Overall diameter24.02"24.04"+0.02"+0.1%
Section width6.89"6.50"−0.39"−5.7%
Sidewall height5.51"5.52"+0.01"+0.2%
Circumference75.47"75.53"+0.06"+0.1%
Revolutions per mile839.5838.8−0.7−0.1%

Speedometer difference

If your vehicle came with 175/80R13 and you fit 165/85R13, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.0 mph0.0 mph
30 mph30.0 mph0.0 mph
40 mph40.0 mph0.0 mph
50 mph50.0 mph0.0 mph
60 mph60.0 mph0.0 mph
65 mph65.1 mph+0.1 mph
70 mph70.1 mph+0.1 mph
75 mph75.1 mph+0.1 mph
80 mph80.1 mph+0.1 mph

Each size on its own

Questions

Which is bigger, 175/80R13 or 165/85R13?
165/85R13 is taller by 0.02 inches (24.04" vs 24.02"). 175/80R13 is wider by 0.39 inches.
Can I replace 175/80R13 with 165/85R13?
Usually, yes. The diameter difference is +0.1%, inside the 3% rule of thumb most tire shops use. Check that the wider or taller tire clears your suspension and fenders, and that its load index meets your placard.
How much will 165/85R13 change my speedometer?
When your speedometer reads 60 mph with 165/85R13 fitted (calibrated for 175/80R13), your real speed is 60.0 mph. Your odometer will under-count miles by about 0.1%.
Will 165/85R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.01 inches of ground clearance at the axle.

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