Wikipedia
Dirtsurfing is the sport of riding a Dirtsurfer brand inline board. This new Australian boardsport is correctly known as inline boarding because Dirtsurfer is a trademark protected brand name.1
A Dirtsurfer is composed of an aircraft aluminium tube frame, a laminate or composite deck and two 20in or 16in diameter BMX style bicycle wheels. Footstraps are (optionally) attached to the deck to give more control to the rider. The board is unique in that it incorporates a patented steering geometry 2 where the front wheel pivots from a point in front of and below the axle of the wheel, via the 'Swingarm'. The rider's weight automatically centres and straightens the front wheel, creating stability and control. Another feature of the Dirtsurfer which is not found on other four-wheeled boards is that, much like a bicycle, the stability actually increases with speed.
Inline Boarding was made an official race class by the International Gravity Sports Association (IGSA) and Gravity Sports International (GSI) in 2005. The 2005 IGSA World Cup Champion inline boarder is Nihat Uysal of Germany.3 Nihat rides the Silver GP-X (see below)