The aspect ratio of a tire is the height of the tire’s sidewall expressed as a percentage of its width.

Quick Scoop

  • The aspect ratio is the second number in a tire size, like the “60” in 215/60R15.
  • It tells you how tall the sidewall is compared to how wide the tire is (sidewall height ÷ tire width × 100).
  • Example: In 215/60R15, the tire is 215 mm wide and the sidewall height is 60% of 215 mm (about 129 mm).
  • A higher aspect ratio = taller sidewall, usually more comfort and flex.
  • A lower aspect ratio = shorter “low‑profile” sidewall, usually sharper handling and sportier look.

So when someone asks “what is the aspect ratio of a tire?”, they’re really asking: what percentage of the tire’s width is its sidewall height, as shown by that middle number on the sidewall?

TL;DR: The tire aspect ratio is the sidewall height as a percentage of the tire’s width, shown as the second number in the size code (e.g., the “60” in 215/60R15).

Information gathered from public forums or data available on the internet and portrayed here.