On January 29, 2005, the French tire maker Michelin made a press release which caught more than one of its competitors by surprise: Michelin claimed the production release of an airless, integrated tire and wheel combination called “Tweel”.
The Tweel had a basic yet revolutionary design: it was made of a series of flexible, V-shaped, shock absorbing polyurethane spokes wrapped in a thin rubber tread and connected to a hub for attachment to a vehicle. Michelin presented the Tweel both with an aluminium hub (for passenger cars) and a deformable hub for other applications. According to Michelin the polyurethane spoke architecture allowed its non-pneumatic tire to “envelope” road hazards while still delivering weight-carrying capacity and ride comfort similar to that of an inflated tire. Further, Michelin claimed to be able to specifically tune the vertical and lateral stiffness of the Tweel thereby pushing ride and handling performances to levels unheard of for pneumatic tires.
Not only was this the first airless tire announcement of a major, established tire manufacturer but more importantly, Michelin claimed its Tweel to be commercially available both for iBOT mobility device and the Segway with tests being underway on an Audi A4.
After a big initial media splash things became quieter around the Tweel and none of Michelin’s claimed applications seemed to be making significant commercial headway:
Segway: Although there are still plenty of images found on the internet showing Segways mounted with Tweels a quick check of the Segway website shows that the Tweel is not the standard issue tire on any current Segway model. Why both companies stopped working together is not clear.
iBOT: According to one unconfirmed report, some iBOTs were initially available with Tweels but users complained about noise and heat build-up of the tires.This is quite surprising given that the iBOT is not a high speed application. But this also shows that commercializing a non-pneumatic technology like the Tweel is a significant challenge even for a tire giant such as Michelin which has one of the most renowned R&D teams in the industry. In any case, Independence Technology L.L.C., the maker of the iBOT wheelchair announced in 2009 that it would discontinue the production and selling of the iBOT.
Audi A4: Reports of the Tweel – Audi A4 tests emerged describing the tires as generating excessive noise and vibrations at higher speeds making them unsuitable for the passenger car market. To be fair to Michelin, they acknowledged themselves that the A4 was a stretch application for the Tweel and that lower speed, lower weight applications would be their first target markets.
Given the Tweel’s lack of commercial success a lot of people in the tire industry started claiming that Michelin used the Tweel as a pure marketing stunt without ever having the intention of commercializing this technology. I don’t believe this to be true though the press coverage of the Tweel alone may well have made up for the development cost.
Michelin has a long history of innovation in the tire industry and they have never been afraid to take their chances in commercializing new tires technologies. The French tire maker has some great successes to its name such as the radial ply technology and silica based treads but also some well known failures such as the PAX system. The latter has become iconic enough to serve as an example in innovation literature, most recently in the book “The Wide Lens” by Ron Adner.
At the time of this writing no further information on a potential release of the Tweel or even Tweel release date are available. However, Michelin has always claimed that the Tweel would be a long term project and that technical maturity for advanced applications would be years if not decades away. One can only congratulate Michelin for having the guts to embark on such a high risk, long term endeavor and hope that their persistence will pay off one day.