Tyre Size Notation Explained
Every tyre sold in the UK carries a standardised marking on its sidewall — for example, 205/55R16 91V. Each part of this code tells you something specific about the tyre's dimensions and capabilities. This guide breaks down what every number and letter means, lists common UK sizes by car type, and explains speed ratings and load indices.
Reading the Sidewall Code
205 / 55 R 16 91 V
The section width (205) is measured in millimetres from sidewall to sidewall when the tyre is mounted on its recommended rim. The aspect ratio (55) means the sidewall height is 55% of 205 mm, so roughly 113 mm. Together with the rim diameter these figures determine overall tyre diameter, which affects speedometer accuracy, gearing and ride height.
Common UK Tyre Sizes by Car Type
| Car Type | Typical Sizes | Examples |
|---|---|---|
| City car | 165/65R14, 175/65R14 | Fiat 500, VW Up!, Toyota Aygo |
| Supermini | 185/65R15, 195/55R16 | Ford Fiesta, VW Polo, Vauxhall Corsa |
| Hatchback / Saloon | 205/55R16, 225/45R17 | Ford Focus, VW Golf, BMW 3 Series |
| Estate / Family | 205/55R16, 225/50R17 | Skoda Octavia, Ford Mondeo |
| SUV / Crossover | 215/65R16, 235/55R18 | Nissan Qashqai, Kia Sportage |
| Large SUV / 4×4 | 255/55R19, 275/45R20 | Range Rover, BMW X5, Audi Q7 |
| Performance car | 225/40R18, 245/35R19 | BMW M3, Mercedes-AMG, Audi RS |
| Van / Light commercial | 215/65R16C, 225/65R16C | Ford Transit, Mercedes Sprinter |
The “C” suffix on van tyres indicates a commercial-rated reinforced casing.
Speed Ratings
| Rating | Max Speed (mph) | Max Speed (km/h) | Typical Use |
|---|---|---|---|
| N | 87 | 140 | Winter / spare tyres |
| P | 93 | 150 | Small city cars |
| Q | 99 | 160 | Winter tyres, 4×4 |
| R | 106 | 170 | Light commercial vehicles |
| S | 112 | 180 | Family cars, MPVs |
| T | 118 | 190 | Family cars, estates |
| H | 130 | 210 | Sporty hatchbacks, saloons |
| V | 149 | 240 | Performance cars |
| W | 168 | 270 | High-performance sports cars |
| Y | 186 | 300 | Supercars, hypercars |
You must always fit tyres with a speed rating at least equal to your car's top speed — fitting lower-rated tyres is an MOT failure. Check your vehicle handbook or the tyre placard (usually on the driver's door frame) for the manufacturer's specified rating.
Load Index Table
| Index | Max Load (kg) | Index | Max Load (kg) |
|---|---|---|---|
| 71 | 345 | 91 | 615 |
| 75 | 387 | 94 | 670 |
| 79 | 437 | 97 | 730 |
| 82 | 475 | 100 | 800 |
| 85 | 515 | 104 | 900 |
| 88 | 560 | 107 | 975 |
The load index is the maximum weight each tyre can safely carry at the speed indicated by the speed rating. Multiply by four for the total vehicle load capacity from tyres. Never fit tyres with a lower load index than your manufacturer specifies.
Related Calculators
Use our free tyre and wheel calculators to compare sizes, check compatibility and more:
- Tyre & Wheel Calculators — full suite of tyre size, diameter, and wheel offset tools
Tyre size markings follow the European Tyre and Rim Technical Organisation (ETRTO) standard. Always refer to your vehicle's handbook or door placard for the manufacturer's recommended tyre size, load index and speed rating.