It is illegal to have a car on the road if:
- A tyre is unsuitable for the use to which the vehicle to trailer is being put or not suitable relative to the other types of tyres fitted.
- The tyres are not properly inflated
- Any tyre fitted to the vehicle has a cut or break in the rubber in excess of 25m or 10% of the section width in length, which exposes the casing cords.
- Any tyre fitted to the vehicle has a lump or bulge caused by separation or partial failure of its structure.
- Any tyre fitted to the vehicle has any portion of the ply or cord exposed.
- Tyres of different structure (i.e. diagonal (cross) ply or radial ply or belted bias) are fitted on the same axle.
- Radial tyres are fitted on the front axle with diagonal (cross) ply tyres on the rear axle.
- The grooves on the tread pattern of every tyre fitted to the wheels of the vehicle do not have a depth of at least 1.6mm throughout a continuous band comprising the central three quarters of the breadth of the tread and around the entire outer circumference of the tyre.