Alloy wheels are considered by many to be a purely aesthetic accessory that is only bought to change the appearance of the car. What you may not realize, is that there are a number of technical reasons why you might want to fit alloy wheels to your vehicle.
Most new vehicles come fitted with steel wheels as standard because they are cheaper, although many manufacturers are recognizing the demand for alloy wheels and fit new cars with them, or at least offer them as an optional upgrade.
'Unsprung Weight'
First among the positives for alloy wheels, is that they reduce the 'unsprung weight' of the wheels. The 'unsprung weight' is the weight of everything connected to the wheel and includes the wheel itself, the tyre, the brakes (if they are fitted within the wheel), spindles, bearings and even a portion of the weight of the half shafts, springs and suspension links.
It is important that the 'unsprung weight' is as low as possible to maintain the optimum contact with the road surface. If it is too high, the suspension will be slow to react, due to the inertia built up by the weight of the wheel. By reducing the 'unsprung weight', the suspension can react to imperfections in the road surface more quickly, maintaining better traction.
Other Weight Issues
One thing to remember is that the wheel is a moving part and builds up inertia, so its weight has more importance than that of a stationary part, like the axle. The heavier it is, the more energy it will require to get it up to speed and to slow it down. By fitting alloy wheels you will reduce the amount of energy required to do this.
On top of this, the overall weight of the vehicle will be reduced which, combined with the above, will have favorable repercussions for the performance of such things as acceleration, fuel consumption and braking.
Brake Performance
As mentioned above, the reduced weight of the vehicle and the wheel itself will help with the performance of the brakes. But it is not just the weight that will help the brakes.
Alloy wheels are able to dissipate heat built up by the brakes more quickly than their steel counterparts. This is due to both the material they are made from and because of their additional 'slots' allowing more air to flow over a greater surface area.
This better brake performance will reduce the risk of brake failure and increase their life expectancy.
Tyre Options
By choosing to fit alloy wheels to your car you will open up the possibilities for fitting wider tyres and tyres with a lower profile.
There are a few benefits to using these types of tyres. They will improve the steering 'feel', steering will also be more responsive and there will be less camber distortion while cornering, they have a lower rolling resistance which will help acceleration and fuel consumption, there will be improved side wall stability under braking and they will allow for the fitting of larger brakes.
Cons
There are some down sides that you may want to consider when looking at purchasing alloy wheels.
- They need to be washed on a regular basis in order to maintain the finish.
- You need to be careful which products you use when cleaning them as some chemicals will damage the finish rather than maintain it.
- You need to take more care when parking at the side of the road. You don't want to spend money on a set of beautiful alloy wheels then scratch them up by hitting the curb. Plus you may invalidate the manufacturer's warranty by doing this.
- You may find that the ride comfort is reduced, particularly if you are running lower profile tyres.
Conclusion
All in all there are many positive technical reasons why you might like to invest in a set of alloy wheels. They may require an initial outlay of money, but depending on how much you spend, you could find that they even save you money in the long run, what with the better fuel consumption and increased brake life expectancy.
But let's face facts. If you're considering purchasing a set of alloy wheels, it's most likely because you want your car to look cool and you want to show off to your mates. All this information provides you with is a way to justify spending the money to your girlfriend, wife or even yourself!
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