You can't reinvent the wheel, but you can reinvent the tire. Colorado tire maker BriTek has unveiled an airless tire for bicycles that does away with the need to repair flats. The Energy Return Wheel is made from two layers of rubber stretched over a 29-inch carbon fiber wheel.

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The space between the two layers of rubber contains a scaffolding of rods and cushions that allows the tire to give and react to compression. While riding, the compressed wheel stores elastic potential energy stored that's released as forward momentum. Hence "energy return." The tire is still in the prototype stage and no date has been set for sale.