From wikipedia *The Tweel (a portmanteau of tire and wheel) is a
prototype tire designed by Michelin. The tire uses no air and
therefore cannot burst or become flat. Instead, flexible
polyurethane spokes are used to support an outer rim. Handling
gains have been cited as a reason to adopt this type of motor
vehicle tire. If problems with the prototypes (such as excess
vibration and noise at higher speed) are resolved, the first
applications for the tire may be in the military where a flat-proof
tire would be advantageous to maneuvering vehicles in difficult or
dangerous areas. *Currently, the Tweel is being used for low-speed,
low-weight applications, such as wheelchairs and construction
equipment (for example, a skid loader). Tests on production cars
have shown it is within 5% of a conventional tire and wheel's
rolling resistance. If Michelin's prototypes go as planned, models
for cars may appear around 2016. *The Tweel has been presented in a
variety of applications. Eventually it may be able to outperform
conventional tires since it can be designed to have high lateral
strength (for better handling) without a loss in comfort. *The
Tweel consists of a cable-reinforced band of conventional "tire"
rubber with molded tread, a shear band just below the tread that
creates a compliant contact patch, and a series of energy-absorbing
polyurethane spokes. The rectangular spokes can be designed to have
a range of stiffnesses, so engineers can control how the Tweel
handles loads. The inner hub contains a matrix of deformable
plastic structures that flex under load and return to their
original shape.
