Tire Size Box

175/70R14 vs 175/80R14

175/80R14 compared with 175/70R14

+5.8% diameter, 0.0" width

175/80R14 is 25.02" tall vs 23.65". More than the 3% rule of thumb, so check carefully before switching.

23.6"14" rim4.8"6.9" wide
175/70R14 (solid) compared with 175/80R14 (dashed outline), drawn to scale

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

63.5 mph

175/80R14 is +1.38 inches (+5.8%) in overall diameter. That is more than the 3% most shops and makers recommend.

175/70R14175/80R14Difference%
Overall diameter23.65"25.02"+1.38"+5.8%
Section width6.89"6.89"0.00"0.0%
Sidewall height4.82"5.51"+0.69"+14.3%
Circumference74.29"78.61"+4.33"+5.8%
Revolutions per mile852.9806.0−47.0−5.5%

Speedometer difference

If your vehicle came with 175/70R14 and you fit 175/80R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.7 mph+1.7 mph
40 mph42.3 mph+2.3 mph
50 mph52.9 mph+2.9 mph
60 mph63.5 mph+3.5 mph
65 mph68.8 mph+3.8 mph
70 mph74.1 mph+4.1 mph
75 mph79.4 mph+4.4 mph
80 mph84.7 mph+4.7 mph

Each size on its own

Questions

Which is bigger, 175/70R14 or 175/80R14?
175/80R14 is taller by 1.38 inches (25.02" vs 23.65"). 175/70R14 is the same width.
Can I replace 175/70R14 with 175/80R14?
It is not recommended without checking carefully. The diameter difference is +5.8%, 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 175/70R14), your real speed is 63.5 mph. Your odometer will under-count miles by about 5.8%.
Will 175/80R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.69 inches of ground clearance at the axle.

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