Cars In The Future : Tyres
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With active safety systems that improve a vehicles stability becoming more common, the integrity of the contact between the vehicle and the road becomes more essential.
It is important that drivers frequently check their tyres for damage, the correct pressure, and tread wear. There are also design improvements that can be made to tyres to increase their safety in different circumstances.
Tyres can be designed specifically for use in the low temperatures that are commonly found in the winter. According to figures supplied by Continental, at 7° Celsius the rubber in the tyres starts to solidify and become harder, this decrease in flexibility means that the tyre becomes less able to grip the road surface.
The compound of winter tyres is designed to remain elastic in the cold weather, and provide better grip with the road surface. The result is of course, shorter stopping distances at low temperatures when compared to standard tyres in the same conditions.
Generally the concept behind winter tyres is good; however, there need to be more research performed which looks at the details. What is the effect on stopping distances over a range of temperatures? Do standard tyres give a better performance at higher temperatures? If so, what is the best advice to give to a driver when the temperature is fluctuating around 7°C over a period of time?
The ideal date and length of time when winter tyres should be fitted will vary dramatically across the UK due to the geographical and meteorological differences.
Further more, standards need to be set to ensure that all tyres branded as winter tyres give the same level of performance in the temperatures they are designed to be more effective in, and temperatures they are not.
In conventional tyres, the pressurised air contained within the tyre supports the weight of the car. However, recently tyres have been developed which are able to support the weight of the car by themselves, for a short period of time. These are known as runflat tyres.
Runflat tyres can support the weight in several different ways; however, the most common approach taken by tyre manufacturers is to increase the thickness and strength of the tyres sidewall.
Whilst runflat tyres can support the vehicle and possibly prevent the severe consequences from a suddenly deflated tyre, they can suffer internal damage when deflated and should not be used at speeds or distances greater than the manufacturer recommends. The runflat capacity allows a driver to pick a safer and more secure place to deal with the deflated tyre although ideally, the tyre should be used in this uninflated state for as short a time and distance as possible.
Runflat tyres should not be retrofitted onto a vehicle that was not designed to use them. It is also important that runflat systems are also accompanied with a Tyre Pressure Monitoring System that will alert the driver if the tyre has deflated, and allow him or her to take appropriate and immediate action.
Tests to guarantee a minimum operational safety level need to be set, to assure that the tyre has adequate runflat capability. Markings on the tyre sidewall can indicate that the tyre has runflat capabilities and has passed these tests.
Tyre Pressure Monitoring Systems
Tyre Pressure Monitoring Systems are designed to give the driver feedback about the pressure in the tyres without the driver having to check the tyres himself.
There are several different types of system available, all of which work to a varying degree of accuracy. It is important that a driver is aware of the accuracy of a tyre pressure monitoring system before getting in the vehicle and using it. It is also still just as essential for drivers to check their tyres frequently as many systems cannot detect a slow equal deflation in all of the tyres.
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