Tire Size Box

165/85R13 vs 185/85R13

185/85R13 compared with 165/85R13

+5.6% diameter, +0.8" width

185/85R13 is 25.38" tall vs 24.04". More than the 3% rule of thumb, so check carefully before switching.

24.0"13" rim5.5"6.5" wide
165/85R13 (solid) compared with 185/85R13 (dashed outline), drawn to scale

With 185/85R13 tires, when your speedometer says 60 mph you are really going

63.3 mph

185/85R13 is +1.34 inches (+5.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

165/85R13185/85R13Difference%
Overall diameter24.04"25.38"+1.34"+5.6%
Section width6.50"7.28"+0.79"+12.1%
Sidewall height5.52"6.19"+0.67"+12.1%
Circumference75.53"79.74"+4.21"+5.6%
Revolutions per mile838.8794.6−44.2−5.3%

Speedometer difference

If your vehicle came with 165/85R13 and you fit 185/85R13, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.1 mph+1.1 mph
30 mph31.7 mph+1.7 mph
40 mph42.2 mph+2.2 mph
50 mph52.8 mph+2.8 mph
60 mph63.3 mph+3.3 mph
65 mph68.6 mph+3.6 mph
70 mph73.9 mph+3.9 mph
75 mph79.2 mph+4.2 mph
80 mph84.5 mph+4.5 mph

Each size on its own

Questions

Which is bigger, 165/85R13 or 185/85R13?
185/85R13 is taller by 1.34 inches (25.38" vs 24.04"). 185/85R13 is wider by 0.79 inches.
Can I replace 165/85R13 with 185/85R13?
It is not recommended without checking carefully. The diameter difference is +5.6%, 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 185/85R13 change my speedometer?
When your speedometer reads 60 mph with 185/85R13 fitted (calibrated for 165/85R13), your real speed is 63.3 mph. Your odometer will under-count miles by about 5.6%.
Will 185/85R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.67 inches of ground clearance at the axle.

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