Bridgestone Air Free tyre nears production

Through leather, iron, wood, rubber and silica, the covering around our wheels has certainly evolved over time. But the pneumatic tyre familiar to the modern motor vehicle is essentially unchanged from the ring-shaped hoop John Boyd Dunlop devised way back in 1887.

OK, we're understating things just a little. But the air-filled rubber hoop we recognise as a tyre today certainly looks quite different to the latest innovation from Bridgestone.

The second-generation prototype of what the Japanese tyre maker calls the Air Free tyre does away with the conventional ring-shaped 'balloon' that currently connect our cars to the road. In its place, dozens of shock-absorbing resin bands, all set at an angle, act as clever little spokes.

Similar to the carcass of a regular tyre, the fins as encased by a thin, patterned band of solid rubber, which is replaceable in much the same way as a retread. Bridgestone says the idea is to banish the flat tyre forever, eliminate centrifugal growth (a result of friction and ambient temperature) and also improve recyclability.

In the US alone more than 285 million car tyres are scrapped annually – a small portion are recycled and some are retreaded, but most end up in landfill or, even worse, as fuel in waste-fired powerplants.

Used tyres release a host of dangerous chemicals when burnt, including a range of hydrocarbons. Left to break down in landfill, the tyre releases a portion of zinc into the surrounding soil, and the heavy metal eventually makes its way into waterways.

The benefits of a reusable Air Free tyre therefore seem obvious, as Bridgestone Europe's technical head Olivier Monbet explains.

"Every part of the [Air Free] tyre is recyclable," said Monbet.

Bridgestone's engineer said the tyre was currently quite stiff and that the manufacturer would work to reduce the lateral rigidity of the Air Free tyre before it reaches production.

Monbet said it was hard to gauge just how expensive the tyre would be in relation to its conventional counterparts, but admits that like any product the cost of production will decrease as production increases.

Bridgestone isn't the first tyre manufacturer to experiment with airless tyre technology. Michelin last year premiered its Tweel and in 2013 Hankook unveiled its i-Flex. BriTek Tire also trialled its Energy Return Wheel for military vehicles and bicycles in 2012, though to date none of these new technologies have reached a state of commercial viability.

Bridgestone says its Air Free tyre will likely reach production within the next two to four years. It will likely premiere as an OEM fit on Toyota's next-generation i-Road single-passenger electric vehicle as part of a small, Tokyo-based trial.