Monday 10 August 2009

For the Sake of Your Car Tyres: Wheel Alignment

Most garages selling car tyres offer a wheel alignment service but not all customers know what this is or what it’s for when they come to buy new tyres. As its name suggests, wheel alignment is to ensure that your car’s wheels are parallel to each other and perpendicular to the ground. Aren’t the wheels like this anyway? They should be but wear and tear, especially that aggravated by speed bumps, can put the wheels out of alignment, as can damage caused by touching a kerb or hitting carriageway debris. Misalignment can cause a braking car to pull to one side or the other, give inaccurate steering and drastically shorten tyre life.

What is involved?

There are usually three factors to be checked and if necessary, adjusted.

The first test is to ensure the wheels are vertical as viewed from the front of the car – this is checking the camber angle.

The second check is slightly more complicated. A car’s front wheels are turned from side to side when you steer. Imagine looking at a front wheel from the side of the car. If you had X-ray vision, you’d see that the steering pivot isn’t vertical but leans back at the top, towards the rear of the car. This is the castor angle, which, if out of adjustment, can cause all manner of strange steering behaviour when you drive.

The third and last check is the tracking. Again looking from the front, the car tyres are usually ‘cross-eyed’, they ‘toe-in’. This is so slight you can’t see it but the setting is important. The tyres are generally set to toe-in so that the when the car is driven, the forces acting on the front wheels and suspension make the front wheels run parallel to one another. If the tyres ‘toe-out’ (think Marty Feldman) through misalignment, or toe-in too much, steering accuracy will suffer and tyre wear will increase. On many cars it’s also possible for the rear wheels to be misaligned.

Should car tyres be worn through misalignment and/or have worn or damaged steering or suspension parts, or even the wrong tyre pressures, correct alignment could be difficult or impossible. The technician will ensure you know about what, if anything, needs adjusting, repairing or replacing.

Man at Work

Wheel alignment used to be achieved with mirrors, weights and string. But such paraphernalia is old hat now; technicians usually use computerised, laser-equipped measuring installations. With these, they can measure and adjust wheel alignment quickly and extremely accurately. So while you enjoy a refreshing cup of tea or visit the shops, your car’s wheels will be aligned with precision, which will extend the life of your car tyres.

What is involved?

How can you keep them this way? Simple – all that’s needed is a little care when you drive. Avoid any debris on the road and watch out for potholes. Take your time over speed pads and straddling speed bumps damages tyres and suspension; drive so that only the wheels on one side of the car go over the bump. Most importantly, when manoeuvring, do not hit kerbs.

Why not drop in to Merityre and get your tyres checked?

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