Tyre Size Guide
How to Read Your Tyre Size
Use the markings on your tyre sidewall to choose the correct size before ordering new tyres. A typical example is: 225/45R17 94W. If this is your size, you can go straight to our 225/45R17 tyres.
For a full list of sizes, visit our Tyre Size Index to jump directly to the right tyres by size page.
What Each Part of Your Tyre Size Means
Using the example 225/45R17 94W:
- 225 – tyre width in millimetres
- 45 – aspect ratio (% of width, the sidewall height)
- R – radial construction (standard for modern tyres)
- 17 – rim diameter in inches
- 94 – load index (how much weight each tyre can carry)
- W – speed rating (maximum safe speed)
Once you know this code, you can quickly find the correct tyre in our Tyre Size Index or browse popular sizes like: 175/65R15 tyres, 215/40R18 tyres or 215/55R17 tyres.
Tyre Speed Rating Chart
The speed rating is the final letter (for example the W in 94W). Always choose a tyre with a speed rating that matches or exceeds the original specification.
| Rating | Max speed |
|---|---|
| T | 190 km/h (118 mph) |
| H | 210 km/h (130 mph) |
| V | 240 km/h (149 mph) |
| W | 270 km/h (168 mph) |
| Y | 300 km/h (186 mph) |
If you are unsure which rating you need, check your handbook or contact us before ordering new car, van & 4x4 tyres.
Tyre Load Index (Examples)
The load index is the number before the speed rating (for example 94W). It shows the maximum weight per tyre. Here are some common examples:
| Index | Max load (kg) |
|---|---|
| 88 | 560 kg |
| 91 | 615 kg |
| 94 | 670 kg |
| 98 | 750 kg |
Never fit tyres with a lower load index than originally specified. If you carry heavy loads or drive a van, you may need reinforced / XL van tyres with a higher load index.
Where to Find Your Tyre Size
- On the sidewall of your current tyres (e.g. 205/55R16 91V)
- Inside the driver’s door frame on a sticker
- In your vehicle handbook
- Sometimes on the fuel cap label
Once you know the code, use our Tyre Size Index to go straight to the correct size and order your new tyres online with fast UK delivery.
Why Choosing the Correct Tyre Size Matters
- Safe handling, braking and grip in all conditions
- Correct speedometer and odometer readings
- Better fuel economy and even tread wear
- Protection for suspension, steering and alloy wheels
- Helps you stay MOT and insurance compliant
If you’re not sure which size you need, our team at PWT Europe Ltd can help you pick the right car tyres, 4x4 / SUV tyres, van tyres or truck tyres.
Need Help? Free Tyre Size Advice
Still unsure about your tyre size, load index or speed rating? We’re happy to check it for you before you order.
Call us: 07511 984 234
Or send a message via our Contact Us page.
For more detailed guides, visit our Tyre Guides & News.