Cardiff Tyre Laws: What Every Driver Needs to Know

In the UK, the legal minimum tread depth for car tyres is 1.6mm across the central three-quarters of the tread, around the complete circumference. This applies equally to all cars driven on Cardiff's roads. There is no exemption for age of vehicle, value of vehicle, or how infrequently the car is used.

Police can stop any vehicle and check tyre tread depth using a calibrated gauge. If a tyre is found to be below 1.6mm, the penalty is a £2,500 fine and three penalty points — per tyre. Drive with four illegal tyres and you're looking at £10,000 in fines and 12 penalty points, which is an automatic ban.

The law requires not just adequate tread depth but that tyres are in a safe condition overall. Tyres with sidewall damage, bulges, exposed cords, or structural failure are illegal regardless of tread depth. The same applies to tyres with large cuts or lacerations.

Mismatched tyres — fitting tyres of different types (radial vs cross-ply) or significantly different sizes on the same axle — are also illegal. Always ensure both tyres on the same axle are the same construction type, size, and ideally the same brand and specification.

Tyre condition and tread depth are checked as part of the annual MOT test. An advisory will be issued if tread depth is between 1.6mm and 3mm. A major failure (failing the MOT) will be recorded for tread below 1.6mm, any tyre damage, or incorrect tyre sizes.

Don't wait for your MOT to check your tyres. The MOT is an annual snapshot — your tyres could become illegal within days of a successful test if they're close to the limit. Check tread depth every month and after any significant impact.