Tire Size Box

175/70R16 vs 175/80R16

175/80R16 compared with 175/70R16

+5.4% diameter, 0.0" width

175/80R16 is 27.02" tall vs 25.65". More than the 3% rule of thumb, so check carefully before switching.

25.6"16" rim4.8"6.9" wide
175/70R16 (solid) compared with 175/80R16 (dashed outline), drawn to scale

With 175/80R16 tires, when your speedometer says 60 mph you are really going

63.2 mph

175/80R16 is +1.38 inches (+5.4%) in overall diameter. That is more than the 3% most shops and makers recommend.

175/70R16175/80R16Difference%
Overall diameter25.65"27.02"+1.38"+5.4%
Section width6.89"6.89"0.00"0.0%
Sidewall height4.82"5.51"+0.69"+14.3%
Circumference80.57"84.90"+4.33"+5.4%
Revolutions per mile786.4746.3−40.1−5.1%

Speedometer difference

If your vehicle came with 175/70R16 and you fit 175/80R16, 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 mph68.5 mph+3.5 mph
70 mph73.8 mph+3.8 mph
75 mph79.0 mph+4.0 mph
80 mph84.3 mph+4.3 mph

Each size on its own

Questions

Which is bigger, 175/70R16 or 175/80R16?
175/80R16 is taller by 1.38 inches (27.02" vs 25.65"). 175/70R16 is the same width.
Can I replace 175/70R16 with 175/80R16?
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 175/80R16 change my speedometer?
When your speedometer reads 60 mph with 175/80R16 fitted (calibrated for 175/70R16), your real speed is 63.2 mph. Your odometer will under-count miles by about 5.4%.
Will 175/80R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.69 inches of ground clearance at the axle.

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