o»i4 Weekly checks
Tyre condition and pressure
l( is very important that tyres are In good condition, and at the correct pressure - having a tyre (allure at any speed is highly dangerous. Tyre wear is influenced by driving style • harsh braking and acceleration, or fast cornering, will ail produce more rapid tyre wear. As a general rule, the front tyres wear out faster than the rears. Interchanging the tyres from front to rear ("rotating' the tyres) may result in more even wear. However, if this is completely effective, you may have the expense of replacing ail four tyres at once! Remove any nails or stones embedded In the tread before they penetrate the tyro to cause deflation. If removal of a nail does reveal that
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the tyre has been punctured, refit the nail so (hat its point of penetration is marked. Then Immediately change the wheel, and have the tyre repaired by a tyre dealer. Regularly check the tyres for damage (n the form of cuts or bulges, especially in the sidewails. Periodically remove the wheels, and clean any dirt or mud from the Inside and outside surfaces. Examine the wheel rims for signs of rusting, corrosion or other damage, Light alloy wheels are easily damaged by •kerbing"1 whilst parking; steel wheels may also become dented or buckled. A new wheel Is very often the only way to overcome severe damage.
New tyres should be balanced when they are fitted, but it may become necessary to re-balance them as they wear, or if the balance weights fitted to the wheel rim should fall off. Unbalanced tyres will v/ear more quickly, as will the steering and suspension components. Wheel imbalance is normally signified by vibration, particularly at a certain speed (typically around 50 mph). If this vibration is fett only through the steering, then II Is likely that |ust the front wheels need balancing. H, however, the vibration is felt through the whole car. the rear wheels could be out of balance. Whoel balancing should be carried out by a tyre dealer or garage.
-j Tread Depth • visual check The original tyres have tread wear safety bands {8}, which wiU appear when the tread depth reaches approximately 1.6 mm. The band positions are indicated by a triangular mark on the tyre sidewail (A).
Tyre tread wear patterns
2 Tread Depth * manual check Alternatively, tread wear can be monitored with a simple, inexpensive device known as a tread depth indicator gauge.
2 Tyre Pressure Check Check the tyre pressures regularly with the tyres cold. Do not adjust the tyre pressures immediately alter the vehicle has been used, or an inaccurate setting will result Tyre pressures are shown on page 0*18.
Shoulder Wear Centre Wear Uneven Wear
Underinflatlon {wear an both sides) Under-lnflatton will cause overheating of the tyre, because the tyre will flex too much, and the tread will not sit correctly on the road surface. This will cause a loss of grip and excessive wear, not to mention the danger of sudden tyre failure due to heat build-up. Check and adjust pressures Incorrect wheel camber (wear on one side] Repair or renew suspension parts Hard cornering Reduce speed!
Overinflation Over-inflation will cause rapid wear of the centre part of the tyro tread, coupled with reduced grip, harsher ride, and the danger of shock damage occurring in the tyre casing. Check and adjust pressures
It you sometimes have (o inflate your car's tyres to the higher pressures specified tor maximum load or sustained high speed, don't forget to reduce the pressures to normal afterwards.
Front tyres may wear unevenly as a result of wheel misalignment. Most lyre dealers and garages can check and adjust the wheel alignment (or 'tracking") for a modest charge. Incorrect camber or castor Repair or renew suspension parts Malfunctioning suspension Repair or renew suspension parts Unbalanced wheel Balance tyres Incorrect toe setting Adjust front wheel alignment Note: The feathered edge of I he treed which typifies toe wear is best checked by feel.
