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Introduction
You need good tyres to drive safely. They are your only contact with the road and affect the steering, braking and acceleration of your vehicle.
Your tyres, each with a contact patch on the road of about the size of a large footprint, have to provide ALL of the grip for:
- Steering
- Braking
- Acceleration
They also improve comfort whilst carrying the weight of the vehicle. If you look after them they will work more reliably and last longer. Neglecting them could be expensive in the long run and could even cost you your life.
Every new car type tyre, other than retreads, must meet European standards for load/speed performance and be marked on the sidewall with E or e.
The legal minimum tread depth for car and similar tyres in the United Kingdom and throughout the European Community is 1.6mm throughout a continuous band comprising the central three quarters of the breadth of tread and round the entire outer circumference of the tyre.
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Most car type 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.
Simple and cheap gauges are widely available to give an acceptable guide to tread depth.
One of the features of tyre tread pattern design is to give good grip in wet conditions. Generally speaking available grip reduces as the tyre wears or as the road surface water depth increases and you should reduce speed in such conditions.
The 1.6mm Minimum Limit Applies to:
- Cars and Passenger Vehicles with up to 8 seated passengers - not including the driver
- Motor Vehicles and Light Trailers (including caravans) up to 3500 kg gross vehicle weight
The penalties for offences related to the use of faulty tyres on vehicles are very severe.
In the case of any vehicles, except goods vehicles and vehicles adapted to carry more than eight passengers, 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 equals £5000.
- Tread Depth - a tyre worn below the legal minimum.
- Mixing - an incorrect mixture of radial and cross ply tyres.
- Inflation - a tyre not inflated to make it suitable for the purpose to which the motor vehicle or trailer is being put.
- Cuts - certain long and deep cuts as specified in regulations.
- Lumps, bulges or tears - caused by separation or partial failure of the tyre structure.
- Exposed ply or cord
- Unsuitability -regarding the use to which the motor vehicle or trailer is being put or to the types of tyres fitted to its other wheels.
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The only part of a tyre to wear away in normal use is the tread and it makes both economic and ecological sense to give a new lease of life to an otherwise good tyre by what is now generally known as retreading.
All retread tyres supplied in the United Kingdom must meet the requirements of the British Standard for retreaded tyres, that is, BS AU 144e, and must be marked with the Standard number.*
The British Standard requires strict examination and inspection of retreaded tyres at all stages which results in perfectly acceptable tyres.
The tyre debris, often seen at the side of motorways in particular, does not necessarily come from retreaded tyres.
Retreaded tyres are used extensively on aircraft and in motoring competition.
* Certain foreign made tyres may be acceptable if of an equivalent standard.
There are many dangers in buying part-worn or "second hand" tyres. Their history is unknown and they may have been removed from a vehicle involved in an accident or have been badly damaged by 'kerbing' or similar problems. Repairs may not have been carried out properly, for example to British Standard BS AU 159e.
Regulations control the quality of part-worn tyres offered for sale. They must have been properly examined internally and externally. Some faults only show up when the tyre is inflated. Tread depth must be 2mm minimum across the whole breadth of tread and the tyres must be marked "PART-WORN" adjacent to the E, e or BS marking.
Except in the case of temporary use spare tyres, it is illegal in the United Kingdom, and is certainly dangerous, to mix radial ply and cross ply tyres on the same axle or to have radial ply tyres on the front axle and cross ply tyres on the rear axle. This applies to all two axle motor vehicles whether front or rear wheel drive.
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Correct tyre pressures are vital for balanced braking, maximum grip and maximum tyre life.
Recommended pressures may vary according to load or speed. Look in the Vehicle Handbook, or consult your garage or tyre dealer.
- Wrong Tyre Pressures (high or low) will cause more rapid wear and shorter tyre life.
- Low Tyre Pressures also cause increased fuel consumption and consequently increased air pollution.
Higher than necessary pressures may give an uncomfortable ride and reduce grip due to the smaller area in contact with the road.
Pressures should be checked at least every two weeks and when the tyres are cold. Even a short trip to the local garage will warm up the tyre and raise the pressure. Accurate and reliable gauges are not expensive and will soon pay back their cost. |