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 happens during an MOT tyre check? +
During an MOT, the examiner checks that all tyres are the correct size and speed rating for the vehicle, that tread depth is at least 1.6mm across the central three-quarters, that there are no cuts, bulges, or exposed cords, and that tyres on the same axle are of the same type (e.g. not mixing radial and cross-ply). Incorrect tyre pressure is not an MOT failure but the examiner may issue an advisory.
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.
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.
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.