Tire Size Box

185/65R14 vs 185/75R14

185/75R14 compared with 185/65R14

+6.2% diameter, 0.0" width

185/75R14 is 24.93" tall vs 23.47". More than the 3% rule of thumb, so check carefully before switching.

23.5"14" rim4.7"7.3" wide
185/65R14 (solid) compared with 185/75R14 (dashed outline), drawn to scale

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

63.7 mph

185/75R14 is +1.46 inches (+6.2%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/65R14185/75R14Difference%
Overall diameter23.47"24.93"+1.46"+6.2%
Section width7.28"7.28"0.00"0.0%
Sidewall height4.73"5.46"+0.73"+15.4%
Circumference73.73"78.30"+4.58"+6.2%
Revolutions per mile859.4809.1−50.2−5.8%

Speedometer difference

If your vehicle came with 185/65R14 and you fit 185/75R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.2 mph+1.2 mph
30 mph31.9 mph+1.9 mph
40 mph42.5 mph+2.5 mph
50 mph53.1 mph+3.1 mph
60 mph63.7 mph+3.7 mph
65 mph69.0 mph+4.0 mph
70 mph74.3 mph+4.3 mph
75 mph79.7 mph+4.7 mph
80 mph85.0 mph+5.0 mph

Each size on its own

Questions

Which is bigger, 185/65R14 or 185/75R14?
185/75R14 is taller by 1.46 inches (24.93" vs 23.47"). 185/65R14 is the same width.
Can I replace 185/65R14 with 185/75R14?
It is not recommended without checking carefully. The diameter difference is +6.2%, 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 185/65R14), your real speed is 63.7 mph. Your odometer will under-count miles by about 6.2%.
Will 185/75R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.73 inches of ground clearance at the axle.

Other comparisons