With a unique structure of spokes stretching along the inner sides of the tires supporting the weight of the vehicle, there is no need to periodically refill the tires with air; as a result, the tires require less maintenance. At the same time, the worry of punctures is eliminated.

In addition, the spoke structure is made from thermoplastic resin and, along with the rubber in the tread portion, the materials used in the tires are recyclable, contributing to the efficient use of resources.

Further, by pursuing extremely low rolling resistance and contributing to reductions in CO₂ emissions through use of proprietary technologies, Bridgestone believes it is possible to achieve even higher levels of environmental friendliness and safety. Bridgestone is pursuing this technological development with the aim of achieving a “cradle to cradle” process that proactively maximizes the cyclical use of resources from worn tires into new tires and the use of recyclable resources.

Features of the second-generation tires include:

• Increased versatility through improved load-bearing capabilities and driving performance. Bridgestone is further optimizing the spoke structure by using high-strength but flexible high-performance resin as a material and employing finite element method (FEM) simulations in the design to reduce stress and deformation in the inner part of the tire.

  By doing so, the second generation of “Air Free Concept tire” has increased versatility through improved load-bearing capabilities and driving performance compared with the first generation.

  For the first generation airless concept tire, the test vehicle had a weight of 100 kg (220 lbs) and maximum speed of 6 km/h (3.7 mph). By contrast, the test vehicle for the second generation airless concept tire weighs 410 kg (904 lbs) and maximum speed of 60 km/h (37.3 mph).

• Pursuing low rolling resistance to reduce CO₂ emissions. About 90% of energy loss from tire rolling resistance comes from repeated changes in the shape of tires as they roll. In the second generation of airless tires, Bridgestone has succeeded in making a significant reduction in energy loss by using proprietary materials technologies and simplifying the structure of the tires.

  As a result, these “Air Free Concept tires” have achieved the same level of low rolling resistance as the company’s pneumatic fuel-efficient tires, making possible a contribution to reductions in CO₂ emissions.

Bridgestone’s approach to achieving its environmental mission. Click to enlarge.