The prototype Energy Return Wheel has no air inside, only an internal rubber layer that is stretched and held taut.
Britek Tire and Rubber has been developing an airless tire that can eliminate flats and convert stored energy into forward momentum. The Energy Return Wheel (ERW) has an internal rubber layer, which is stretched and held taut by adjustable rods. Gizmag reports that the tire features a rubber tread on the outside, and a series of elastic cushions in the space between. The bicycle tire also has lightweight 29-inch carbon fiber rims, and is open on the sides.
Some of the benefits of these airless tires are that they make cycling safer and more efficient. Obstacles slide under the ERW wheels with precision and ideal comfort, and keeping the tread on the tire. The tread ride comfort can be fully adjusted to make the wheels run harder or softer. Check out the video below to see the ERWs being used: