GarageCalc What 155/60R15 means
155 is the section width in millimeters (6.1 in). 60 is the aspect ratio: the sidewall is 60 percent of the width, so 155 × 0.60 = 93 mm (3.7 in). R is radial construction, and 15 is the wheel diameter in inches (381 mm). Stack two sidewalls on the wheel and you get the overall diameter: 381 + 2 × 93 = 567 mm, or 22.3 in.
A full marking adds a load index and speed rating after the size, for example 155/60R15 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 155/60R15
Similar diameter does not establish interchangeability. Follow the vehicle manufacturer's approved sizes; see Michelin's tire-size guidance.
No common 16-inch size stays within 3 percent of 22.3 in. Going down one size, 175/60R14 is -0.2% with a taller 105 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.
For the effect on road speed and distance, see our worked speedometer example. When maintaining this set, use the rotation pattern guide to check whether tire direction or different front and rear sizes restrict rotation.
Frequently asked questions
How tall is a 155/60R15 tire?
22.3 inches (567 mm) in overall diameter: the 15-inch wheel (381 mm) plus two 93 mm sidewalls. Actual dimensions depend on the tire model, tread depth, pressure and load; check the tire manufacturer specifications.
What is 155/60R15 in inches?
22.3 x 6.1 R15: 22.3 inches tall, 6.1 inches wide, on a 15-inch wheel. The sidewall is 3.7 inches and the circumference is 70.1 inches, so the tire turns 903 times per mile.
What tire sizes are equivalent to 155/60R15?
Within 3 percent of the same diameter on the same 15-inch wheel: 175/55R15 (+1.1%), 175/50R15 (-1.9%), 165/60R15 (+2.1%); on a 14-inch wheel: 175/60R14 (-0.2%), 165/65R14 (+0.5%). These are nominal diameter comparisons, not approved replacements. Check vehicle-approved sizes, rim width, load and speed ratings, and clearance before changing size.
Can I use 165/60R15 instead of 155/60R15?
Nominal size comparison only: 165/60R15 is 2.1% taller (+12 mm) and 10 mm wider, and at a true 60 mph the speedometer would read 58.8 mph. This does not confirm fitment. Check approved rim widths, load and speed ratings, and vehicle clearances. On the same wheel centerline, the extra nominal width uses about 0.20 in more space on each side, reducing clearance. Actual section width also depends on the tire model and rim width.