Formula Xtreme was a professional racing class sanctioned by the American Motorcyclist Association.
Motorcycles were homologated and had to be of a model type that was designed and legal for street use in the United States and was available from retail dealerships in the U.S.
Although liberal by the standards of other classes AMA road racing series, Formula Xtreme rules still limited the modifications that may have been made.
Lastly, the type of engine (displacement and configuration) was governed by a set of guidelines that attempted to bring technical diversity to the class by establishing technical limitations that allowed different technologies to remain competitive.
Merrill Vanderslice, AMA Pro Racing's Director of Competition, stated: By design, Formula Xtreme rules are the most liberal of all the classes within the AMA Superbike Championship...The intent of the Formula Xtreme class is to include a diverse group of motorcycles...[1] Manufacturers represented in the AMA Formula Xtreme Series included the Big Four; Honda, Kawasaki, Suzuki and Yamaha, and in 2008 BMW, Ducati, Triumph and Buell were represented as well.