Tire Size Box

185/55R14 vs 185/65R14

185/65R14 compared with 185/55R14

+6.6% diameter, 0.0" width

185/65R14 is 23.47" tall vs 22.01". More than the 3% rule of thumb, so check carefully before switching.

22.0"14" rim4.0"7.3" wide
185/55R14 (solid) compared with 185/65R14 (dashed outline), drawn to scale

With 185/65R14 tires, when your speedometer says 60 mph you are really going

64.0 mph

185/65R14 is +1.46 inches (+6.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/55R14185/65R14Difference%
Overall diameter22.01"23.47"+1.46"+6.6%
Section width7.28"7.28"0.00"0.0%
Sidewall height4.01"4.73"+0.73"+18.2%
Circumference69.15"73.73"+4.58"+6.6%
Revolutions per mile916.2859.4−56.9−6.2%

Speedometer difference

If your vehicle came with 185/55R14 and you fit 185/65R14, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph21.3 mph+1.3 mph
30 mph32.0 mph+2.0 mph
40 mph42.6 mph+2.6 mph
50 mph53.3 mph+3.3 mph
60 mph64.0 mph+4.0 mph
65 mph69.3 mph+4.3 mph
70 mph74.6 mph+4.6 mph
75 mph80.0 mph+5.0 mph
80 mph85.3 mph+5.3 mph

Each size on its own

Questions

Which is bigger, 185/55R14 or 185/65R14?
185/65R14 is taller by 1.46 inches (23.47" vs 22.01"). 185/55R14 is the same width.
Can I replace 185/55R14 with 185/65R14?
It is not recommended without checking carefully. The diameter difference is +6.6%, 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 185/65R14 change my speedometer?
When your speedometer reads 60 mph with 185/65R14 fitted (calibrated for 185/55R14), your real speed is 64.0 mph. Your odometer will under-count miles by about 6.6%.
Will 185/65R14 lift my vehicle?
Ride height changes by half the diameter difference: +0.73 inches of ground clearance at the axle.

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