Tire Size Box

185/70R14 vs 185/75R14

185/75R14 compared with 185/70R14

+3.0% diameter, 0.0" width

185/75R14 is 24.93" tall vs 24.20". More than the 3% rule of thumb, so check carefully before switching.

24.2"14" rim5.1"7.3" wide
185/70R14 (solid) compared with 185/75R14 (dashed outline), drawn to scale

With 185/75R14 tires, when your speedometer says 60 mph you are really going

61.8 mph

185/75R14 is +0.73 inches (+3.0%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/70R14185/75R14Difference%
Overall diameter24.20"24.93"+0.73"+3.0%
Section width7.28"7.28"0.00"0.0%
Sidewall height5.10"5.46"+0.36"+7.1%
Circumference76.02"78.30"+2.29"+3.0%
Revolutions per mile833.5809.1−24.4−2.9%

Speedometer difference

If your vehicle came with 185/70R14 and you fit 185/75R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.6 mph+0.6 mph
30 mph30.9 mph+0.9 mph
40 mph41.2 mph+1.2 mph
50 mph51.5 mph+1.5 mph
60 mph61.8 mph+1.8 mph
65 mph67.0 mph+2.0 mph
70 mph72.1 mph+2.1 mph
75 mph77.3 mph+2.3 mph
80 mph82.4 mph+2.4 mph

Each size on its own

Questions

Which is bigger, 185/70R14 or 185/75R14?
185/75R14 is taller by 0.73 inches (24.93" vs 24.20"). 185/70R14 is the same width.
Can I replace 185/70R14 with 185/75R14?
It is not recommended without checking carefully. The diameter difference is +3.0%, 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 185/75R14 change my speedometer?
When your speedometer reads 60 mph with 185/75R14 fitted (calibrated for 185/70R14), your real speed is 61.8 mph. Your odometer will under-count miles by about 3.0%.
Will 185/75R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.36 inches of ground clearance at the axle.

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