Regulations govern many aspects of tyre condition of which the following are the principal points:
Minimum tread depth
- Tyres must be suitable (ie of the correct type and size) for the use to which the vehicle is being put and must be inflated to the vehicle or tyre manufacturers' recommended pressures.
- Tyres of different types must not be fitted to opposite wheels of the vehicle (for example, radial-ply tyres must not be fitted to a wheel on the same axle as wheels already fitted with cross-ply tyres and vice versa, and a two-axle vehicle with single rear wheels must not have radial ply tyres on the front axle if cross ply tyres are fitted to the rear axle – this mix produces oversteer).
- No tyre must have a break in its fabric or a cut deep enough to reach the body cords. No cut must be more than 25mm or 10 per cent of the tyre's section width in length, whichever is the greater.
- There must be no lump, bulge or tear caused by separation or partial fracture of its structure, neither must any portion of the ply or cord structure be exposed.
Tyres on cars, light vans (not exceeding 3,500kg gross weight) and light trailers must have a tread depth of at least 1.6 mm across the central three-quarters of the breadth of tread (ie the width of that part of the tyre which is in contact with the road surface under normal conditions) and in a continuous band around the entire circumference of the tyre.
For goods vehicles over 3.5 tonnes the minimum tread depth requirement remains at 1mm (along with other requirements).
Most car tyres have tread wear indicators, usually at least six small ribs across the bottom of the main tread grooves, and when the tread surface becomes level with these ribs the tyre is at the legal limit and must be replaced.
The penalties for offences related to the use of faulty tyres on vehicles are severe.
In the case of cars and passenger vehicles with up to eight seated passengers – not including the driver – and motor vehicles and light trailers (including caravans) up to 3500 kg gross vehicle weight, for every offence there is a fine at level 4 of the standard scale with discretionary disqualification and compulsory driving licence endorsement with 3 penalty points.
Level 4 is currently £2500 and each faulty tyre is considered as a separate offence. Two faulty tyres equal £5000.
Run-flat and temporary use spare tyres
Regulations permit the legal use of 'run-flat' tyres (provided they are identified as such) in a partially inflated or flat condition, and what are described as temporary use spare tyres. When a temporary use spare tyre is being used, the vehicle speed must not exceed 50 mph, and a special high inflation pressure is normally used, otherwise the legal provision which permits their use ceases to apply. The temporary use spare tyre or the wheel to which it is fitted must be of a different colour to the other wheels on the vehicle and a label must be attached to the wheel giving clear information about the precautions to be observed when it is being used.
It is important to remember that insurance policies will be invalidated by driving on illegal tyres.
The insurance community has seen fit to highlight unsafe tyres as a mitigating factor when apportioning blame at the time of an accident as well as reserving the right to render a vehicle as uninsured. As a result, motorists may at the time of accident find themselves exposed to enormous personal financial loss in terms of any vehicles involved, personal injury suffered as well as for property reparation.
Think your tyres need replacing? Check out our UK Tyre dealers listings:
The above auto checklists have been thoroughly researched to be as accurate as possible however, they are intended only as a helpful guide, and Auto Insider will not be held responsible for inaccuracies relating to their content.