not a wheel.. A Tweel

More pics here

Michelin has developed an integrated tire and wheel combination missing one ingredient that is vital for traditional tire performance – air. The “Tweel” is comprised of a deceptively simple looking hub and spoke design that replaces the need for air pressure while delivering performance previously only available from pneumatic tires. The flexible spokes are fused with a flexible wheel that deforms to absorb shock and rebound with ease. Without the air needed by conventional tires, Tweel still delivers pneumatic-like performance in weight-carrying capacity, ride comfort, and the ability to “envelope” road hazards.

Michelin has also found that it can tune Tweel performances independently of each other, which is a significant change from conventional tires. As a result, vertical stiffness (which primarily affects ride comfort) and lateral stiffness (which affects handling and cornering) can both be optimized, pushing the performance envelope in these applications and enabling new performances not possible for current inflated tires. The Tweel prototype, demonstrated on the Audi A4, is within five percent of the rolling resistance and mass levels of current pneumatic tires. That translates to within one percent of the fuel economy of the OE (Original Equipment) fitment. Additionally, Michelin has increased the lateral stiffness by a factor of five, making the prototype unusually responsive in its handling.