Where to Find Your Tyre Size
Your size is moulded into every sidewall. Look for a sequence of numbers and letters such as 225/45 R17 91W. It will be on both front and rear (though front and rear sizes can differ on some vehicles).
You can also find the recommended size in your vehicle handbook, or on a sticker inside the driver’s door frame or fuel filler flap.
The width in millimetres, measured from sidewall to sidewall.
Sidewall height as a percentage of the width. 45% of 225mm = 101mm sidewall height.
R = Radial. The vast majority of modern fitments are radial construction.
The diameter of the wheel rim it fits, measured in inches.
The maximum load it can carry. 91 = 615kg per corner.
Maximum speed it is rated for. W = 270km/h (168mph).
Common Speed Ratings
| Letter | Max Speed | Typical Use |
|---|---|---|
| T | 190 km/h (118 mph) | Family cars, light vans |
| H | 210 km/h (130 mph) | Sports saloons, estate cars |
| V | 240 km/h (149 mph) | Performance cars |
| W | 270 km/h (168 mph) | High-performance cars |
| Y | 300 km/h (186 mph) | Super/sports cars |
Can I Fit a Different Size?
You must fit the size specified for your vehicle. Fitting the wrong size affects speedometer accuracy, handling, load capacity and MOT compliance. Always match the size on your current fitment or in your vehicle handbook.
Run-Flat Tyres
Run-flat tyres are marked ROF, RFT, SSR or similar depending on the manufacturer. They can be driven on at reduced speed after a puncture. Not all vehicles are compatible with run-flats.
