Across a century or more, tyres – the crucial part of each and every automobile suspension have evolved in more ways than we can imagine. Better safety, better handling, improved fuel economy and an extended life are the most common grounds competitively and constantly updated and worked upon by tyre companies all over the world. To be true, tyres are soon to be self capable of regenerating treads and increase their own life – as claimed to be the next magic trick out of Michelin’s bag.
Almost all tyres share some common basic and extremely important components that are also they’re building blocks.
Bead, Plies, Rubber, Steel etc are some of these vital organs that constitute a tyre. A bead is a high-strength loop made out of a steel cable and coated with rubber. The bead provides the tyre with strength to keep it snapped on the wheel rim and to be able to handle multiple forces that act on the tyre due to the air pressure acting outward, and also when its been mounted on the rim manually or by a tyre mounting machine.
The body constitutes of several different fabric layers called plies. Polyester cord is a commonly used ply fabric. In radial tires, the cords run perpendicular to the tyre treads. Earlier tires were also diagonally biased at times – their fabric ran at an angle to the treads. Plies are also rubber coated to provide for better bonding with outer components and sealing in the air. Plies also play a role in determining the strength of the tyre by their number. The number of plies also varies from tyre to tyre on the basis of purpose of built. For example, an average car tyre can have upto to two plies or more where as a passenger plane employs tyres with upto thirty plies or more.
Steel-belted radials employ actual steel belts in order to reinforce the area under the treads, and to provide for resistance to punctures and keep the tyres flat to achieve better road contact.
High-speed tyres have extra layers of polyester fabric to provide better hold on the components in place and are called cap plies.
Sidewalls serve the purpose of lateral stability, protecting the body plies and keeping the air inside under all conditions of driving. They may also have additional components to aid lateral stability.
Last and definitely not the least, treads provide for traction and driving stability and are made up of different kinds of natural and synthetic rubbers compounded together. Treads and sidewalls are first extruded and then cut to length. Tread patterns have a design element called the rain groove. Rain grooves are specifically arranged to channel water away from the footprint. They are circumferential in truck tyres. Tyre manufacturers also claim to have designed grooves that help pump water out from under the tyre by tread-flexing action.
There have been numerous explorations in design innovation and manufacturing technology of tires. Michelin’s Infinicoil technology, Tweel – Airless tyre – that has small flexible spokes extended outward from the central hub to support the treads. There is no air inside, only flat rubber connected to the spokes. Hankook’s new airless “i-flex” concept has also created quite a sensation at the concept launch.
The i-flex tyre is all in one tyre and rim combination that is puncture proof. The lack of rubber makes it lighter than almost all popular tires of the day. Ninety five percent of the materials in the tyre are recyclable.
Hankook is also working the “e-membrane” concept, which is a tyre that actually transforms and changes shape as per the driving condition input. the central part of the tyre moves inward and outward with the speed of the vehicle. Low speeds let the tyre have the centre line sucked inward to allow for lesser rolling resistance and better fuel economy. At high speeds the centre comes level with the edges and takes full contact with the road to provide grip and required traction.
Coda Development, have innovated a system called the SIT – Self inflating tyre. that keeps the tyre pressure constant with a valve that pulls in outside air forcefully into the rubber. At optimal pressure, the valve shuts the intake of air, and circulates it inside the tyre. Eliminating the chances of improper air pressure leading to blowouts and rollovers and hence contributing heavily to the safety aspect.
Tires have and will continue to define the way we drive. They’re like shoes. Simple, sleek, or swanky, but always built for a specific purpose – stability, safety and drive quality.