The numbers and letters on your tyre sidewall might look confusing, but they tell you everything you need to know. Here's our simple guide to decoding them.
Every tyre has a series of numbers and letters moulded into its sidewall. These markings contain crucial information about the tyre's size, performance capabilities, and age. Understanding them helps you buy the right replacement tyres and stay safe on the road.
Breaking Down the Tyre Size: 205/55R16 91V
| Marking | Meaning | Example |
|---|---|---|
| 205 | Tyre width in millimetres | 205mm wide |
| 55 | Aspect ratio (sidewall height as % of width) | 55% of 205mm = 112.75mm |
| R | Radial construction | Most modern tyres are radial |
| 16 | Rim diameter in inches | Fits a 16-inch wheel |
| 91 | Load index (max weight per tyre) | 91 = 615kg per tyre |
| V | Speed rating (max safe speed) | V = up to 149mph |
Speed Ratings Explained
The speed rating letter indicates the maximum speed the tyre is designed for. Common ratings include: T (118mph), H (130mph), V (149mph), W (168mph), and Y (186mph). Always fit tyres with at least the speed rating specified by your vehicle manufacturer.
Finding the DOT Date Code
The four-digit DOT code tells you when the tyre was manufactured. For example, 2524 means the tyre was made in week 25 of 2024. Tyres older than 5-6 years should be inspected regularly, and most manufacturers recommend replacement after 10 years regardless of tread depth.
Not sure what size tyres you need? Use our tyre finder tool — just enter your registration and we'll show you the right sizes with instant pricing.
