Tire Size Box

155/75R13 vs 155/85R13

155/85R13 compared with 155/75R13

+5.5% diameter, 0.0" width

155/85R13 is 23.37" tall vs 22.15". More than the 3% rule of thumb, so check carefully before switching.

22.2"13" rim4.6"6.1" wide
155/75R13 (solid) compared with 155/85R13 (dashed outline), drawn to scale

With 155/85R13 tires, when your speedometer says 60 mph you are really going

63.3 mph

155/85R13 is +1.22 inches (+5.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

155/75R13155/85R13Difference%
Overall diameter22.15"23.37"+1.22"+5.5%
Section width6.10"6.10"0.00"0.0%
Sidewall height4.58"5.19"+0.61"+13.3%
Circumference69.60"73.43"+3.83"+5.5%
Revolutions per mile910.4862.8−47.5−5.2%

Speedometer difference

If your vehicle came with 155/75R13 and you fit 155/85R13, 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 mph79.1 mph+4.1 mph
80 mph84.4 mph+4.4 mph

Each size on its own

Questions

Which is bigger, 155/75R13 or 155/85R13?
155/85R13 is taller by 1.22 inches (23.37" vs 22.15"). 155/75R13 is the same width.
Can I replace 155/75R13 with 155/85R13?
It is not recommended without checking carefully. The diameter difference is +5.5%, 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 155/85R13 change my speedometer?
When your speedometer reads 60 mph with 155/85R13 fitted (calibrated for 155/75R13), your real speed is 63.3 mph. Your odometer will under-count miles by about 5.5%.
Will 155/85R13 lift my vehicle?
Ride height changes by half the diameter difference: +0.61 inches of ground clearance at the axle.

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