Tire Size Box

155/70R14 vs 155/80R14

155/80R14 compared with 155/70R14

+5.4% diameter, 0.0" width

155/80R14 is 23.76" tall vs 22.54". More than the 3% rule of thumb, so check carefully before switching.

22.5"14" rim4.3"6.1" wide
155/70R14 (solid) compared with 155/80R14 (dashed outline), drawn to scale

With 155/80R14 tires, when your speedometer says 60 mph you are really going

63.2 mph

155/80R14 is +1.22 inches (+5.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

155/70R14155/80R14Difference%
Overall diameter22.54"23.76"+1.22"+5.4%
Section width6.10"6.10"0.00"0.0%
Sidewall height4.27"4.88"+0.61"+14.3%
Circumference70.82"74.66"+3.83"+5.4%
Revolutions per mile894.6848.7−45.9−5.1%

Speedometer difference

If your vehicle came with 155/70R14 and you fit 155/80R14, 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 mph42.2 mph+2.2 mph
50 mph52.7 mph+2.7 mph
60 mph63.2 mph+3.2 mph
65 mph68.5 mph+3.5 mph
70 mph73.8 mph+3.8 mph
75 mph79.1 mph+4.1 mph
80 mph84.3 mph+4.3 mph

Each size on its own

Questions

Which is bigger, 155/70R14 or 155/80R14?
155/80R14 is taller by 1.22 inches (23.76" vs 22.54"). 155/70R14 is the same width.
Can I replace 155/70R14 with 155/80R14?
It is not recommended without checking carefully. The diameter difference is +5.4%, 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 155/80R14 change my speedometer?
When your speedometer reads 60 mph with 155/80R14 fitted (calibrated for 155/70R14), your real speed is 63.2 mph. Your odometer will under-count miles by about 5.4%.
Will 155/80R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.61 inches of ground clearance at the axle.

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