Airless tire

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Non-pneumatic tires (NPT), or Airless tires, are tires that are not supported by air pressure. They are used on some small vehicles such as riding lawn mowers and motorized golf carts. Tires composed of closed-cell polyurethane foam are also made for bicycles and wheelchairs. The main advantage of airless tires is that they cannot go flat, but they are far less common than airfilled tires.

Airless tires generally have higher rolling friction and provide much less suspension than similarly shaped and sized pneumatic tires. Other problems that have plagued airless tires include dissipating the heat buildup that occurs when they are driven. Airless tires are often filled with compressed polymers (plastic), rather than air.

Michelin is currently developing an integrated tire and wheel combination, the "Tweel", that operates entirely without air.