This is dependent on the car and how it is driven but the legal limit is 1.6mm of tread. By law, the tyres will need to be replaced. Once your car tyres reach 3mm of tread, your breaking distance increases massively. Tyres can be checked against age, wear and cracking, all of which contribute to your safety and the safety of your car. You can book in at any of our Chapelhouse garages for a free-of-charge health check where your tyres will be checked.