Peter Cooper Car Repairs

17 Wintersells Road Byfleet Surrey KT14 7LF

01932 340384





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Tyre laws


Tyre safety and the law

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.

Here you will find out about the legal requirements and the precautions you should take to ensure that the tyres on your vehicle are safe.

What your tyres do

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 must meet European standards for load/speed performance and be marked on the sidewall with E or e.

Tread depth

The legal minimum tread depth of the main grooves of car and similar tyres in the United Kingdom is 1.6mm. This applies across the central three quarters of the breadth of tread and round the entire outer circumference of the tyre.

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 also available to give an acceptable guide to tread depth.

breadth of tread

The 1.6mm minimum limit applies to:

  • cars and passenger vehicles with up to 8 seated passengers - not including the driver
  • Motor vehicles & light trailers (including caravans) up to 3500Kg gross vehicle weight

Retreaded Tyres

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 comply with the British Standard for retreaded tyres, BS AU 144e, and must be marked with the Standard number. (Certain foreign made tyres may be acceptable if of an equivalent standard).

The British Standard requires strict examination and inspection of retreaded tyres at all stages and they must meet the same load/speed performance standards as new tyres.

The tyre debris, often seen at the roadside, does not necessarily come from retreaded tyres and is mainly the result of under inflation or overloading.

Retreaded tyres are used extensively on aircraft and in motoring competition.

Part-worn tyres

There are many dangers in buying part-worn or 'second-hand' tyres. Their history is unknown and they may have been 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 Standards BS AU 159f.

Regulations require a part-worn tyre to be marked 'PART-WORN' adjacent to the E, e or BS mark, to indicate that it has been properly examined internally and externally before being offered for sale. Some faults only show up if the tyre has been inflated.

Tread depth must be at least 2 mm across the whole breadth of tread.

Mixing of tyres

Except in the case of temporary use spare tyres, it is illegal in the United Kingdom, and it 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. The type of tyre is indicated on the sidewall markings. In the case of radial ply tyres, the letter 'R' is part of the tyre size marking as in the example below, and in addition the word 'Radial' may be shown on the sidewall.

175/65 R 14 82T

Tyre pressures

Correct tyre pressures are vital for safe handling and optimum braking, grip and tyre life.

  • Low tyre pressures or overloading will cause increased fuel consumption, more air pollution, shorter tyre life and greater risk of tyre failure.
  • High tyre pressures may cause reduced comfort, less grip, greater risk of impact tyre damage and reduced stability in braking and cornering.

Pressures should be checked at least every two weeks and only 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.

Recommended pressures may vary according to load or speed. Look in the vehicle handbook, or consult your garage or tyre dealer.

Your vehicle data


Make _________________________________________

Model _________________________________________

Year ___________________________________________



Size ____________________

* Pressure Normal ________________________

* Pressure heavy load/high speed ________________________



Size ____________________

* Pressure Normal __________________

* Pressure heavy load/speed ______________

* See vehicle handbook or ask your garage or tyre dealer

Equivalent Pressures

kPa bar lb/in2(psi) kPa bar lb/in2(psi)
150 1.5 22.0 200 2.0 29.0
160 1.6 23.0 210 2.1 30.5
170 1.7 24.5 220 2.2 32.0
180 1.8 26.0 230 2.3 33.5
190 1.9 27.5 240 2.4 35.0



The penalties for offences related to the use of faulty tyres on vehicles are very severe.

In the case of any vehicle, 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.

Offences can relate to:

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.

We welcome new customers from the local area Cobham Byfleet West Byfleet Addlestone Chertsey Esher Weybridge Walton on Thames Ripley Woking  and the surrounding area.