GarageCalc What 185/55R14 means
185 is the section width in millimeters (7.3 in). 55 is the aspect ratio: the sidewall is 55 percent of the width, so 185 × 0.55 = 102 mm (4.0 in). R is radial construction, and 14 is the wheel diameter in inches (356 mm). Stack two sidewalls on the wheel and you get the overall diameter: 356 + 2 × 102 = 559 mm, or 22.0 in.
A full marking adds a load index and speed rating after the size, for example 185/55R14 91V. Those two codes set how much weight and speed the tire is certified for; look them up in the load index chart and the speed rating chart.
Plus and minus sizing from 185/55R14
Similar diameter does not establish interchangeability. Follow the vehicle manufacturer's approved sizes; see Michelin's tire-size guidance.
Going up one wheel size, the closest match is 175/50R15 at -0.6% diameter with a 88 mm sidewall instead of 102 mm. Going down one size, 175/65R13 is -0.3% with a taller 114 mm sidewall for more comfort and pothole margin. The 3 percent cutoff is a comparison filter, not a fitment approval. Use vehicle-approved sizes and check rim width, load and speed ratings, and clearances. The comparison calculator shows the full speedometer table for any pair.
Frequently asked questions
How tall is a 185/55R14 tire?
22.0 inches (559 mm) in overall diameter: the 14-inch wheel (356 mm) plus two 102 mm sidewalls. Actual dimensions depend on the tire model, tread depth, pressure and load; check the tire manufacturer specifications.
What is 185/55R14 in inches?
22.0 x 7.3 R14: 22.0 inches tall, 7.3 inches wide, on a 14-inch wheel. The sidewall is 4.0 inches and the circumference is 69.2 inches, so the tire turns 916 times per mile.
What tire sizes are equivalent to 185/55R14?
Within 3 percent of the same diameter on the same 14-inch wheel: 165/60R14 (-1.0%), 175/60R14 (+1.2%), 165/65R14 (+2.0%); on a 15-inch wheel: 175/50R15 (-0.6%), 175/55R15 (+2.6%); on a 13-inch wheel: 175/65R13 (-0.3%), 165/70R13 (+0.4%). The percentage is the diameter change, which is also your speedometer error.