What is the minimum permissible depth of the tyre tread pattern of a lorry?
Show the correct answer
Correct answer
B. 1.6 mm.
Explanation
The question is about the minimum permitted depth of the tyre tread pattern on a lorry. It is 1.6 mm - answer B.
The Regulation on the technical conditions of vehicles prohibits fitting a vehicle with tyres whose indicators show the limit of tread wear, and, for tyres without such indicators, tyres with a tread pattern depth of less than 1.6 mm. Wear indicators are small raised bars in the tread grooves, marked on the side of the tyre with the letters TWI or a triangle: when the tread is level with them, the tyre must be replaced. The value of 3 mm (answer A) is a requirement only for a bus approved to travel at 100 km/h, and 2.6 mm (answer C) does not come from any rule; for a lorry the legal limit is 1.6 mm, although experts recommend replacing tyres earlier, because with a shallow tread the tyre drains water less well and aquaplaning is more likely.
Legal basis: § 11 para. 7 point 4 of the Regulation of the Minister of Infrastructure on the technical conditions of vehicles and the scope of their necessary equipment