Tire Size Box

185/50R16 vs 185/55R16

185/55R16 compared with 185/50R16

+3.1% diameter, 0.0" width

185/55R16 is 24.01" tall vs 23.28". More than the 3% rule of thumb, so check carefully before switching.

23.3"16" rim3.6"7.3" wide
185/50R16 (solid) compared with 185/55R16 (dashed outline), drawn to scale

With 185/55R16 tires, when your speedometer says 60 mph you are really going

61.9 mph

185/55R16 is +0.73 inches (+3.1%) in overall diameter. That is more than the 3% most shops and makers recommend.

185/50R16185/55R16Difference%
Overall diameter23.28"24.01"+0.73"+3.1%
Section width7.28"7.28"0.00"0.0%
Sidewall height3.64"4.01"+0.36"+10.0%
Circumference73.15"75.44"+2.29"+3.1%
Revolutions per mile866.2839.9−26.3−3.0%

Speedometer difference

If your vehicle came with 185/50R16 and you fit 185/55R16, 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 mph41.3 mph+1.3 mph
50 mph51.6 mph+1.6 mph
60 mph61.9 mph+1.9 mph
65 mph67.0 mph+2.0 mph
70 mph72.2 mph+2.2 mph
75 mph77.3 mph+2.3 mph
80 mph82.5 mph+2.5 mph

Each size on its own

Questions

Which is bigger, 185/50R16 or 185/55R16?
185/55R16 is taller by 0.73 inches (24.01" vs 23.28"). 185/50R16 is the same width.
Can I replace 185/50R16 with 185/55R16?
It is not recommended without checking carefully. The diameter difference is +3.1%, 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 185/55R16 change my speedometer?
When your speedometer reads 60 mph with 185/55R16 fitted (calibrated for 185/50R16), your real speed is 61.9 mph. Your odometer will under-count miles by about 3.1%.
Will 185/55R16 lift my vehicle?
Ride height changes by half the diameter difference: +0.36 inches of ground clearance at the axle.

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