How do I read my tyre size? +
Your tyre size is printed on the sidewall in a format like 205/55R16 91V. The first number (205) is the width in millimetres, the second (55) is the aspect ratio as a percentage of the width, R means radial construction, and 16 is the wheel diameter in inches. The number after (91) is the load index and the letter (V) is the speed rating. Your vehicle handbook and the sticker inside the driver's door frame show the correct size for your car.
What should I do if I get a flat tyre on the motorway? +
Pull onto the hard shoulder as far left as possible, switch on your hazard lights, and exit the vehicle from the passenger side away from traffic. Do not attempt to change a tyre on the motorway hard shoulder — it is extremely dangerous. Move behind the crash barrier if there is one, then call a mobile tyre fitter or breakdown service. If you are on a smart motorway with no hard shoulder, stop in an emergency refuge area.
What is the legal minimum tyre tread depth in the UK? +
The legal minimum tread depth in the UK is 1.6mm across the central three-quarters of the tyre, around its entire circumference. However, most motoring organisations recommend replacing tyres at 3mm, as braking performance drops significantly below this level. Driving on tyres below 1.6mm carries a fine of up to £2,500 and 3 penalty points per illegal tyre — so four bald tyres could mean a £10,000 fine and 12 points.
What are run-flat tyres and can any fitter work on them? +
Run-flat tyres have reinforced sidewalls that support the weight of the car even with no air pressure, allowing you to drive up to 50 miles at 30mph after a puncture. They require specialist fitting equipment and a TPMS reset after replacement. Not all garages can work on run-flat tyres, but most professional mobile fitters and tyre centres are fully equipped. Run-flat tyres are typically 20–40% more expensive than standard equivalents.
Are part-worn tyres safe to buy? +
Part-worn tyres carry significant risks. While they are legal to sell in the UK, studies have found that a large proportion fail to meet legal standards — many have been previously repaired improperly, have internal damage not visible from the outside, or are close to the legal tread limit. The small saving is rarely worth the risk. New budget tyres from reputable brands often cost only £15–£25 more and come with a full warranty.
What does the TPMS warning light mean? +
The TPMS (Tyre Pressure Monitoring System) warning light indicates that one or more of your tyres has dropped below the recommended pressure. This could be caused by a slow puncture, a change in temperature, or simply natural air loss over time. Do not ignore it — under-inflated tyres increase braking distances and can overheat at speed. Check your pressures at the nearest petrol station or call a mobile tyre fitter.