About 7 years ago, Michelin began to seriously toss around the idea of making an airless tire for mass-production. Since the invention of the pneumatic tire in 1846, people have always wondered if there would be an effective way to make a tire that was immune to flats and low air pressure. Called the Tweel, Michelin’s prototype looked to be a promising alternative to the airless tire. Michelin claimed that the Tweel could achieve tread life of about 2 to 3 times that of a conventional tire and about 5 times the lateral stiffness, great for high-performance sports cars. The only real downsides to the Tweel were a slight increase in rolling resistance and a noticeable increase in road noise – which Michelin attributed to spoke vibrations. For whatever reason though, Michelin went silent about progress on the Tweel. Some believe that the Tweel was just too much trouble and didn’t pan out while others believe that Michelin has started working on a top-secret military contract for the Tweel. It could simply be that Michelin just doesn’t want to give away too many findings to its competition.
This is where Bridgestone comes in. Late in 2011, Bridgestone announced at the Tokyo Auto Show in Japan that they had developed a prototype airless tire. This design looks highly similar to Michelin’s Tweel; featuring thermoplastic-resin spokes that radiate from the rim to the tread. Bridgestone seems to not be worried about road-noise and excess vibrations with their design but are still trying to sort out a few issues, mainly keeping rocks and debris out of the pliant spokes.
Needless to say, after an extended hiatus it seems as though the airless tire could be closer to making its appearance than ever before! We can only hope that the infrastructure can handle such a drastic change. Perhaps rubber tubes filled with high pressure air will be a novelty of the past and something our grandchildren laugh disbelievingly at someday soon.