Dirtsurfing is the term used to describe 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.

A Dirtsurfer is composed of an aircraft aluminum tube frame, a laminate or composite deck and two 20in or 16in diameter BMX style bicycle wheels. The board is unique in that it incorporates a patented steering geometry where the front wheel pivots from a point in front of and below the axle of the wheel. 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, thanks to the gyroscopic action of the large wheels.

This information is taken from wikipedia, click here to read the full article.