Why You Should Regularly Check Your Car Tyres
by RICHARD JENKINS
It is essential that you check your car tyres regularly, for wear, cracking, bulging, pressure or objects caught in the tread. Not only are defective tyres highly dangerous but if found by the police to be defective (that is with a tyre tread of less than 1.6mm across the central 3/4 of the tyre or in any other way not roadworthy) you will face a fine of up to?2500 and 3 penalty points per tyre.
Most car tyres have tread wear indicators, usually six small ribs across the bottom of the main tread grooves. When the tread surface becomes level with these ribs the tyre is at the legal limit and must be replaced.
You should check the pressure of your tyres, including the spare, once a week. Correct tyre pressures result in optimized braking, handling, grip and fuel efficiency. Low tyre pressure will increase your car's fuel consumption, shorten the life of the tyre and increase risk of tyre failure. High tyre pressure will cause diminished grip, reduce stability in braking and cornering and increase risk of impact tyre damage. You must check tyre pressure only when the tyres are cold. Warm tyres, archived by driving no more than a few miles, will provide a false reading. The correct tyre pressure for your particular car will be listed in the owner's manual.
If you don't own a pressure gauge then the easiest way to check tyre pressure is by using a digital air dispenser found at most petrol stations. These are very easy to use and there should be instructions on how to do so on the machine itself.
Most car tyres are made to very high quality standards however there can still be variations in the thickness of the rubber, the steel belts and the radial webbing that forms the structure. This can lead to a slight weight difference around the tyre. This is a well know issue and can be cured by balancing the wheel and tyre. A less well known problem caused by these slight variations is a problem called run-out: a measure of how straight the tyre will run if fitted to a wheel and allowed to roll along a flat level surface.
Some tyres will run straight and true others will veer to the right or left. When buying a new tyre you will see an indication of this. Look for a red or blue line running the tread of the new tyre. this is a run-out indicator. The nearer it is to the centre the straighter the tyre will run and which side of the centre it is on shows the direction of the run-out.
If both tyres on the front axle of your car run-out significantly in the same direction a steering problem can occur. When buying new tyres it is important to go for two with run-outs that are of the same amount but in opposite directions. This way the two will cancel each other out and you have straight steering.
Richard Jenkins is owner of the driving test and driving schools website. A site for learner drivers which provides guides on topics such as the driving theory test and the driving test DVD.
