GarageCalc What 155/65R14 means
155 is the section width in millimeters (6.1 in). 65 is the aspect ratio: the sidewall is 65 percent of the width, so 155 × 0.65 = 101 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 × 101 = 557 mm, or 21.9 in.
A full marking adds a load index and speed rating after the size, for example 155/65R14 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 155/65R14
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 -0.2% diameter with a 88 mm sidewall instead of 101 mm. Going down one size, 175/65R13 is +0.1% 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 155/65R14 tire?
21.9 inches (557 mm) in overall diameter: the 14-inch wheel (356 mm) plus two 101 mm sidewalls. Actual dimensions depend on the tire model, tread depth, pressure and load; check the tire manufacturer specifications.
What is 155/65R14 in inches?
21.9 x 6.1 R14: 21.9 inches tall, 6.1 inches wide, on a 14-inch wheel. The sidewall is 4.0 inches and the circumference is 68.9 inches, so the tire turns 920 times per mile.
What tire sizes are equivalent to 155/65R14?
Within 3 percent of the same diameter on the same 14-inch wheel: 165/60R14 (-0.6%), 175/60R14 (+1.5%), 165/65R14 (+2.3%); on a 15-inch wheel: 175/50R15 (-0.2%), 155/60R15 (+1.8%); on a 13-inch wheel: 175/65R13 (+0.1%), 165/70R13 (+0.7%). The percentage is the diameter change, which is also your speedometer error.
Can I use 165/60R14 instead of 155/65R14?
Nominal size comparison only: 165/60R14 is 0.6% shorter (-4 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 60.4 mph. This does not confirm fitment. Check approved rim widths, load and speed ratings, and vehicle clearances. The nominal extra width adds about 0.20 in of clearance on each side of the tire and a rim width that suits 165 mm.