Supermoto is motorcycle racing on a circuit that alternates between three types of track: flat track, motocross and road racing, using motorcycles designed for that purpose. Supermoto was originally conceived as something like an all-star game, in which the best riders from the three separate genres of motorcycle racing could temporarily leave their normal race class to come together and compete for the title of best all around racer. Today supermoto is a distinct genre of its own and riders in the other classes do not routinely cross over into supermoto.
Races are commonly held on road racing or medium sized go-kart tracks with an off-road section in the infield. Most supermoto race tracks have a tarmac size of 50-75% and the remaining percentage of the course is off-road. The dirt sections are usually constructed of packed clay and feature motocross style obstacles like bermed corners and jumps. This type of racing is also very portable in that an entire track can be constructed anywhere there is a large area of open asphalt and an availability of dirt. Supermoto races have also been successfully held in busy urban centers using closed city streets for the road course and a vacant lot for the dirt sections.
The motorcycles used are frequently custom-created combinations of off-road motorcycles and road-racing wheels/tires, known as 'supermotard' bikes. Riders also wear a combination of road race and offroad equipment, normally road racing leathers and motocross helmets and boots. Unlike normal motorcycle racing, the emphasis lies on slower speeds—typically less than 100 mph (160 km/h)— on short, technical tracks, where rider skill matters more than outright machine performance.
Check out this video featuring 2006 Moto GP Champion Nicky Hayden and 2010 World Superbike Champion Max Biaggi to see some supermoto action: