Tire Size Box

155/80R14 vs 175/80R14

175/80R14 compared with 155/80R14

+5.3% diameter, +0.8" width

175/80R14 is 25.02" tall vs 23.76". More than the 3% rule of thumb, so check carefully before switching.

23.8"14" rim4.9"6.1" wide
155/80R14 (solid) compared with 175/80R14 (dashed outline), drawn to scale

With 175/80R14 tires, when your speedometer says 60 mph you are really going

63.2 mph

175/80R14 is +1.26 inches (+5.3%) in overall diameter. That is more than the 3% most shops and makers recommend.

155/80R14175/80R14Difference%
Overall diameter23.76"25.02"+1.26"+5.3%
Section width6.10"6.89"+0.79"+12.9%
Sidewall height4.88"5.51"+0.63"+12.9%
Circumference74.66"78.61"+3.96"+5.3%
Revolutions per mile848.7806.0−42.7−5.0%

Speedometer difference

If your vehicle came with 155/80R14 and you fit 175/80R14, 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 mph42.1 mph+2.1 mph
50 mph52.7 mph+2.7 mph
60 mph63.2 mph+3.2 mph
65 mph68.4 mph+3.4 mph
70 mph73.7 mph+3.7 mph
75 mph79.0 mph+4.0 mph
80 mph84.2 mph+4.2 mph

Each size on its own

Questions

Which is bigger, 155/80R14 or 175/80R14?
175/80R14 is taller by 1.26 inches (25.02" vs 23.76"). 175/80R14 is wider by 0.79 inches.
Can I replace 155/80R14 with 175/80R14?
It is not recommended without checking carefully. The diameter difference is +5.3%, 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 175/80R14 change my speedometer?
When your speedometer reads 60 mph with 175/80R14 fitted (calibrated for 155/80R14), your real speed is 63.2 mph. Your odometer will under-count miles by about 5.3%.
Will 175/80R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.63 inches of ground clearance at the axle.

Other comparisons