ALTHOUGH tyres still look pretty much the same – black and round – as when John Dunlop invented the pneumatic tyre in 1888, much has changed, and continues to change.

Over the past century, developments such as steel and radial belts, tubeless construction and advances in chemical compounds have allowed motorists to take their hard-working tyres for granted.

Goodyear’s SilentArmor technology protects tyres with a belt of Kevlar, normally associated with bullet-proof applications.
Today, we expect tyres to grip well in wet or dry weather, roll along quietly and comfortably, last a long time and resist punctures – all in a cheap package.

Tomorrow’s tyres may be much the same, yet significantly different.

No more flats

One trend that tyre companies and car makers are exploring is the run-flat tyre. The concept is simple – make stiffer sidewalls that are strong enough to support the weight of the vehicle even when all air pressure is lost.

Realising the goal proved to be harder because of problems with comfort and handling. However, tyre engineers have largely overcome them and more cars are rolling out each day with run-flats as original fitment tyres.

BMW has been a pioneer in adopting run-flat technology, with the 1 and 3 Series sedan models, the 6 Series, Z4, Z8 and MINI Cooper S having these new tyres fitted as standard. For the 5 and 7 Series, MINI and MINI Cooper, run-flat tyres are available as options.

The secret behind the run-flat or self-supporting tyre is additional elastic inlays made from an extremely heat-resistant rubber mixture, in the side walls. This prevents the tyre becoming so hot that it bursts into flames.

This is why the self-supporting tyre is able to continue going for distances of up to 150km, with the vehicle fully loaded, despite having lost all of its internal air pressure.

In addition to convenience, the new tyre technology also offers higher safety, particularly in the event of a sudden loss in pressure. BMW’s specially-formed EH2 rims mean that the run-flat tyre does not lose contact with the wheel should air escape suddenly. .

Since run-flat tyres perform and appear normal even after pressure loss, a driver may not even notice that he has suffered a puncture, which is why these tyres are always fitted in combination with a standard Tyre Puncture Indicator (TPI), an indirect form of TPMS.

Armoured

Goodyear’s SilentArmor isn’t exactly bullet-proof, but it does share the technology of ballistic protection vests –Dupont’s Kevlar, a material that is, pound for pound, five times stronger than steel. A layer of this light and super strong fibre reinforces the two steel belts in the tread area against penetration.

Combined with its Durawall sidewall reinforcement technology, Goodyear claims that its Wrangler and Fortera tyres for 4WD vehicles and SUVs offer unmatched levels of strength as well as quietness.

Unfortunately, the SilentArmor tyres are not available in Malaysia, nor are there plans to bring them in. It would be cool to be able to brag about having “bulletproof” tyres to your friends.

Sand tyres

The best thing that has happened to tyres in the past decade is the addition of silica to tread compounds., specifically the carbon black filler material. The addition of silica translates into added traction, enhanced braking performance in the wet, and lower fuel consumption because of lower rolling resistance.

Silica is the common name of silicon dioxide, a compound of silicon and oxygen (SiO2). It is abundant in nature and can be found in many forms, the most common of which is sand.

The benefits of silica in tyres are well known, but the material is also difficult to mix with the other ingredients. Most of the major tyre companies boast proprietary technology that improves the mixing of silica with the vast array of other materials that go into the construction of a single tyre.

The ingredients include fabrics of steel, nylon, aramid fibre, rayon, fibreglass and polyester, or usually a combination of them, such as polyester fabric in the body plies and steel fabric in the belts and beads of most radial passenger tyres. Then, there are hundreds of polymer types of rubber (both natural and synthetic), carbon black, silica, resins, antioxidants, ozonants, paraffin waxes, cure accelerators, activators, sulphur, and processing aids such as oils, tackifiers, peptisers and softeners.

According to Goodyear (www.goodyear.com.my/tyre_school), the most popular size of passenger tyre, a 195/75R14, weighs just under 9kg, and has approximately 2.3kg of 30 different types of synthetic rubber, 1.8kg of eight types of natural rubber, 2.3kg of eight types of carbon black, 0.5kg of steel cord for belts, 0.5kg of polyester and nylon, 0.5kg of steel bead wire and 1.5kg of 40 different kinds of chemicals, waxes, oils, pigments, etc.

So, while all tyres are black and round, there really are quite a number of differences beneath the surface of various brands and types of tyres.

Source
thestar.com.my

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