Tire Size Box

155/85R14 vs 175/85R14

175/85R14 compared with 155/85R14

+5.5% diameter, +0.8" width

175/85R14 is 25.71" tall vs 24.37". More than the 3% rule of thumb, so check carefully before switching.

24.4"14" rim5.2"6.1" wide
155/85R14 (solid) compared with 175/85R14 (dashed outline), drawn to scale

With 175/85R14 tires, when your speedometer says 60 mph you are really going

63.3 mph

175/85R14 is +1.34 inches (+5.5%) in overall diameter. That is more than the 3% most shops and makers recommend.

155/85R14175/85R14Difference%
Overall diameter24.37"25.71"+1.34"+5.5%
Section width6.10"6.89"+0.79"+12.9%
Sidewall height5.19"5.86"+0.67"+12.9%
Circumference76.57"80.78"+4.21"+5.5%
Revolutions per mile827.4784.4−43.1−5.2%

Speedometer difference

If your vehicle came with 155/85R14 and you fit 175/85R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.1 mph+1.1 mph
30 mph31.6 mph+1.6 mph
40 mph42.2 mph+2.2 mph
50 mph52.7 mph+2.7 mph
60 mph63.3 mph+3.3 mph
65 mph68.6 mph+3.6 mph
70 mph73.8 mph+3.8 mph
75 mph79.1 mph+4.1 mph
80 mph84.4 mph+4.4 mph

Each size on its own

Questions

Which is bigger, 155/85R14 or 175/85R14?
175/85R14 is taller by 1.34 inches (25.71" vs 24.37"). 175/85R14 is wider by 0.79 inches.
Can I replace 155/85R14 with 175/85R14?
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 175/85R14 change my speedometer?
When your speedometer reads 60 mph with 175/85R14 fitted (calibrated for 155/85R14), your real speed is 63.3 mph. Your odometer will under-count miles by about 5.5%.
Will 175/85R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.67 inches of ground clearance at the axle.

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