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HOW WHEELS AND TYRES WORK
CarPoint looks beyond the jargon to understand why your car needs wheels and tyres.
The most simple inventions are usually the best, and few are more uncomplicated than the wheel. Have a think about it: there's a small and low-friction contact with the road, and an equally free-spinning connection to the vehicle -- whether it be a buggy or a Bentley. Add power and a sticky rubber wrapping for traction and comfort, and as long as nothing breaks or wears out you have an ongoing method of getting from A to B.
Nobody really knows who invented the wheel. It might have been the proverbial caveman, but was more likely one of the more advanced Middle-Eastern civilisations intent on building, travelling and going to war. The amazing thing is that in essence, those early wheels differ little to what we see today on anything from a Daihatsu Charade to a Formula One Ferrari and perform exactly the same purpose.
In fact, wheels are so straightforward that there's not a lot to say about them other than what they're made of, and what sizes they come in. Take it for granted, their cylindrical shape is here to stay.
Wheels are made from two basic materials. The most common is pressed steel, which has the advantages of being easy and cheaper to manufacturer, and their somewhat downmarket look can be tarted up with plastic wheel trims or hubcaps. They are also strong and somewhat malleable, so any minor damage can be repaired: for instance, beaten back into that desired circular shape if a pothole or rock puts a ding in the outer rim.
Then there's alloy wheels, which as their name suggests are made out of a mixture of steel and lighter metal such as magnesium. Still strong, although perhaps a little more brittle, alloys wheels have the dual advantages of being lighter and so give a car's suspension less reciprocating mass to deal with as they pound over bumps, and they usually look better than the steel items.
This last point can't be overemphasised: most of us choose alloy rims, which come in a vast array of styles and patterns, for aesthetic reasons, and car-makers take advantage of this by charging extra. In high performance or racing cars the pattern of the spokes can be designed to maximise air flow through the wheel and aid in cooling the brakes, but most of time it's simply a design thing appealing to personal taste or lack thereof.
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