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.
Do I need to replace all four tyres at the same time? +
No, you do not need to replace all four tyres at once unless they are all worn. It is best practice to replace tyres in pairs (both fronts or both rears) to maintain even handling. The newer tyres should always go on the rear axle for stability, even on front-wheel-drive cars. Mixing tyre brands on the same axle is not recommended but is acceptable across different axles.
How long does it take to fit a new tyre? +
A single tyre change typically takes 15 to 30 minutes, including removing the old tyre, fitting and balancing the new one, and torquing the wheel nuts to the correct specification. If you are having all four tyres replaced, expect the job to take around 45 minutes to an hour. Mobile fitters work to the same timescales as a garage.
How old can tyres be before they need replacing? +
Even if the tread looks fine, tyres degrade over time as the rubber compound hardens and loses grip. Most manufacturers recommend replacing tyres after 5 years of use, and no tyre should remain in service for more than 10 years from the date of manufacture. You can check the age using the DOT code on the sidewall — the last four digits show the week and year of manufacture (e.g. 2319 means week 23 of 2019).
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.
Can a tyre blowout be repaired or does it need replacing? +
A tyre that has suffered a blowout almost always needs replacing. The internal structure of the tyre is usually destroyed by the sudden loss of pressure and the impact damage that follows. Even if the tyre appears intact, the sidewall and carcass will have been compromised. A tyre fitter can inspect it, but in the vast majority of cases a new tyre is the only safe option.