The Trikke (pronounced "trike") is a human powered, three-wheeled carving vehicle that utilizes conservation of angular momentum to allow a rider to propel forward. The rider alternates leaning side-to-side to move forwards. The width needed to move forward is roughly the width of a downtown sidewalk (1-1.5 m).
A rider may reach speeds of up to 18 mph (29 km/h) on flat ground. It can be used downhill or a level surface. It can move uphill though doing so requires a substantial amount of effort. The whole body needs to be used in a synchronized movement.
In 1988, Brazilians Gildo Beleski and Osorio Trentini were inspired to create a three-wheeled vehicle for riding downhill — three wheels because they felt that the stability of three wheels combined with the frame’s dynamic ability to lean or camber would offer much greater turning ability at speed. While slowing down on the flat after the speed run, they discovered that the vehicle would continue to move forward as long as he continued to turn it.