What do these numbers mean? Let's break it down so you can understand tyre sizes for any vehicle or truck tyre.
When you look at the sidewall of a tyre, you’ll see a series of numbers and letters like:
275/70 R 22.5(example only)
But what do these numbers mean? Let’s break it down so you can understand tyre sizes for any vehicle or truck tyre.
These markings are printed on the sidewall of every tyre and follow a standard format, so you can compare and understand sizes across different tyre brands and types.
Example of how to read tyre sizes — understanding width, profile, and rim using a typical tyre marking.
1. Tyre Width
The first number (e.g. 275) is the width of the tyre in millimetres. This is the measurement from one side of the tread to the other.
2. Profile / Aspect Ratio
The second number (e.g. 70) is called the aspect ratio or profile. It’s the height of the tyre’s sidewall as a percentage of its width.
For example, if the width is 275 mm, and the profile is 70, the sidewall height is 70% of 275 mm.
3. Construction
The letter R stands for Radial construction, which is the industry standard for most modern tyres.
4. Rim Diameter
The last number (e.g. 22.5) is the rim diameter in inches. This tells you what size wheel the tyre fits onto.
