Calculate Your Tyre Size
Understanding tyre size markings helps you choose the correct tyre for your vehicle. This guide explains how tyre sizing works, what the markings mean and how load and speed ratings fit into the full tyre size code.
Steps to Calculate Your Tyre Size
Learn to calculate your tyre size by understanding what the sidewall markings on your tyres stand for. Knowing the correct tyre size for your vehicle is crucial for optimal performance and safety.
Take the guesswork out of the equation and learn the precise measurements you need with our tyre size calculator. Whether you're a seasoned driver or a novice, our tyre size calculator article will help you purchase the right size tyres every time.
Tyre size information is located on the sidewall of your tyre. Follow the breakdown below to understand tyre size markings.
| Sidewall Marking | Explanation |
|---|---|
| 205 | The width of the tyre in millimetres |
| 55 | The height of the tyre sidewall as a percentage of the width |
| R | The type of tyre construction |
| 16 | The tyre’s inner diameter in inches |
| 91 | The load rating of the tyre |
| W | The speed rating – the tyre’s maximum speed at full load |
Get to know your tyres
Now you know what each value stands for, it's time to work out what it all means.
Tyre Load Rating
The tyre load rating is usually found between the diameter reading and the speed rating on the sidewall marking.
This rating shows how much a tyre should be able to carry when inflated to its recommended pressure.
Tyres are made to withstand a certain amount of weight. An overloaded tyre has a higher risk of low pressure or blowing out.
Tyre Speed Rating
The final letter indicates what speeds the tyres can safely reach when fitted to a vehicle.
| Speed Symbol | Max Speed mph | Max Speed km/h |
|---|---|---|
| M | 81 | 130 |
| Q | 99 | 160 |
| S | 112 | 180 |
| T | 118 | 190 |
| H | 130 | 210 |
| V | 149 | 240 |
| W | 168 | 270 |
| Y | 186 | 300 |
I've calculated my tyre size, now what?
Now that you know how to calculate the size of your tyres, you can browse our tyre catalogue to find tyres that are suitable for your vehicle.
Our range includes premium, mid-range and budget tyres, each with their own features and technologies to suit the needs of many drivers.
