All you need to know about car tyres for safe driving
Four small patches of rubber each about the size of your hand are the only parts of the car in touch with the road.
The right tyres, in good condition and correctly inflated are vital for braking and cornering safety – and the only things keeping the car on the road.
Regular checks and maintenance will help to prolong the life of the tyres and keep you on the right side of the law too.
ORIGINAL FIT CAR TYRES
For new cars the car maker and tyre manufacturers work closely to select a make, size and tread pattern that suits the car. Styling, handling, noise and many other factors are taken into account.
When replacing your tyres you must stick to the same size, type and ideally brand and tread pattern too. This is likely to be the tyre best suited to the car. Changing brand or pattern could result in increased noise or adversely affect cornering characteristics for example.
NEW TYRES TO THE FRONT OR REAR?
Check the car manual first as some vehicle manufacturers give specific advice on this. If there is no information in the manual, then it’s good practice for safety to fit the best/newest tyres on the rear. In wet conditions, this favours understeer rather than oversteer. So if you have the front tyres renewed it’s best to have the rear ones moved to the front and the new tyres fitted to the rear.
BASIC LEGAL REQUIREMENTS
• Tyres must be compatible with others on the car and generally be in good physical condition
• Tyres must be correctly inflated to the vehicle manufacturer’s recommended pressure
• Tread depth must be above the legal minimum which for passenger cars is 1.6mm throughout a continuous band in the centre 3/4 of the tread and around the entire circumference
• You don’t have to carry a spare and it doesn’t have to meet the legal requirements while it’s stowed away.
TYRE PRESSURE
Tyre pressures are quoted for cold tyres and will be specified in your car manual. They may also be shown on a sticker inside the fuel filler cap or driver’s door.
Generally two figures will be quoted; one for ‘normal’ use and a higher figure for full loads. You should make sure to adjust the pressures as required.
If you don’t know the correct tyre pressures you can contact the vehicle manufacturer’s customer services department.
Correct tyre pressure is important for several reasons:
• Tyre life – under or over inflation increases wear
• Fuel economy – under inflation increases fuel consumption
• Safety – under or over inflation will affect grip and braking performance
• Ride – over inflation can result in a harsh, uncomfortable ride
You should check tyre pressures every two weeks when the tyres are cold using a reliable tyre pressure gauge.
At the same time, examine the tyres for any cuts or bulges. If you find any, have them checked out by a professional as soon as possible. A bulge in a tyre indicates internal structural damage so the tyre will need to be replaced.
The tyre must also be replaced if you find cuts deep enough to reveal the internal structure of the tyre.
REINFORCED OR EXTRA LOAD TYRES FOR MPVS
Tyres for Space Wagons/Multi Purpose Vehicles.
Heavy vehicles and loads place greater demands on the tyres. They run hotter and would be more susceptible to failure if they were not of the correct specification.
Most Multi-Purpose-Vehicles (mpvs) are heavier and can carry more load than a car of similar size. As a result most MPV manufacturers now specify reinforced, extra load or commercial tyres.
Though it may not be mentioned specifically in the manual that the vehicle is fitted with reinforced tyres it’s important to make sure that any replacement tyres match the tyres fitted when the car was new.
MARKINGS
To check if your vehicle is fitted with extra load capacity tyres look for the following markings on the tyre sidewall:
• XL – Extra Load
• RNF – Reinforced
• C – Commercial
If you’re unsure which specification of tyre should be fitted to your car you should contact the vehicle manufacturer or one of their appointed dealers.