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. They
are also used on heavy equipment such as backhoes, which are required
to operate on sites such as building demolition, where tire punctures
are likely. 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 air
filled tires.
