Tire Size Box

155/75R14 vs 175/75R14

175/75R14 compared with 155/75R14

+5.1% diameter, +0.8" width

175/75R14 is 24.33" tall vs 23.15". More than the 3% rule of thumb, so check carefully before switching.

23.2"14" rim4.6"6.1" wide
155/75R14 (solid) compared with 175/75R14 (dashed outline), drawn to scale

With 175/75R14 tires, when your speedometer says 60 mph you are really going

63.1 mph

175/75R14 is +1.18 inches (+5.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

155/75R14175/75R14Difference%
Overall diameter23.15"24.33"+1.18"+5.1%
Section width6.10"6.89"+0.79"+12.9%
Sidewall height4.58"5.17"+0.59"+12.9%
Circumference72.74"76.45"+3.71"+5.1%
Revolutions per mile871.1828.8−42.3−4.9%

Speedometer difference

If your vehicle came with 155/75R14 and you fit 175/75R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.0 mph+1.0 mph
30 mph31.5 mph+1.5 mph
40 mph42.0 mph+2.0 mph
50 mph52.6 mph+2.6 mph
60 mph63.1 mph+3.1 mph
65 mph68.3 mph+3.3 mph
70 mph73.6 mph+3.6 mph
75 mph78.8 mph+3.8 mph
80 mph84.1 mph+4.1 mph

Each size on its own

Questions

Which is bigger, 155/75R14 or 175/75R14?
175/75R14 is taller by 1.18 inches (24.33" vs 23.15"). 175/75R14 is wider by 0.79 inches.
Can I replace 155/75R14 with 175/75R14?
It is not recommended without checking carefully. The diameter difference is +5.1%, 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 175/75R14 change my speedometer?
When your speedometer reads 60 mph with 175/75R14 fitted (calibrated for 155/75R14), your real speed is 63.1 mph. Your odometer will under-count miles by about 5.1%.
Will 175/75R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.59 inches of ground clearance at the axle.

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