Tire Size Box

185/55R16 vs 205/55R16

205/55R16 compared with 185/55R16

+3.6% diameter, +0.8" width

205/55R16 is 24.88" tall vs 24.01". More than the 3% rule of thumb, so check carefully before switching.

24.0"16" rim4.0"7.3" wide
185/55R16 (solid) compared with 205/55R16 (dashed outline), drawn to scale

With 205/55R16 tires, when your speedometer says 60 mph you are really going

62.2 mph

205/55R16 is +0.87 inches (+3.6%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/55R16205/55R16Difference%
Overall diameter24.01"24.88"+0.87"+3.6%
Section width7.28"8.07"+0.79"+10.8%
Sidewall height4.01"4.44"+0.43"+10.8%
Circumference75.44"78.16"+2.72"+3.6%
Revolutions per mile839.9810.7−29.2−3.5%

Speedometer difference

If your vehicle came with 185/55R16 and you fit 205/55R16, here is your real speed for each speedometer reading:

Speedometer showsActual speedDifference
20 mph20.7 mph+0.7 mph
30 mph31.1 mph+1.1 mph
40 mph41.4 mph+1.4 mph
50 mph51.8 mph+1.8 mph
60 mph62.2 mph+2.2 mph
65 mph67.3 mph+2.3 mph
70 mph72.5 mph+2.5 mph
75 mph77.7 mph+2.7 mph
80 mph82.9 mph+2.9 mph

Each size on its own

Questions

Which is bigger, 185/55R16 or 205/55R16?
205/55R16 is taller by 0.87 inches (24.88" vs 24.01"). 205/55R16 is wider by 0.79 inches.
Can I replace 185/55R16 with 205/55R16?
It is not recommended without checking carefully. The diameter difference is +3.6%, 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 205/55R16 change my speedometer?
When your speedometer reads 60 mph with 205/55R16 fitted (calibrated for 185/55R16), your real speed is 62.2 mph. Your odometer will under-count miles by about 3.6%.
Will 205/55R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.43 inches of ground clearance at the axle.

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