calipers that clamp onto oversized vented rotors. Suspension systems are advanced in terms of adjustments and materials for increased stability and durability. Front and rear tires are larger and wider than tires found on other types of motorcycles to allow higher cornering speeds and greater lean angles. Fairings may or may not be used on a sport bike; when used, fairings are shaped to reduce aerodynamic drag as much as possible and provide wind protection for the rider. The combination of rider position, location of the engine and other heavy components, and the motorcycle's geometry help maintain structural integrity and chassis rigidity, and determine how it will behave under acceleration, braking, and cornering. Correct front-to-rear weight distribution is of particular importance to the handling of sport bikes, and the changing position of the rider's body dynamically changes the handling of the motorcycle. Because of the complexity of modeling all the possible movements of different sized riders, to approach perfect tuning of a motorcycle's weight distribution and suspension is often only possible by having a bike customized or at least adjusted to fit a specific rider. Generally, road racing style sport bikes have shorter wheelbases than those intended for more comfortable touring, and the current trend in sport bike design is towards shorter wheelbases, giving quicker turning at the expense of a greater tendency for unintentional wheelies and stoppies under hard acceleration and braking, respectively. Some motorcycles have anti-wheelie systems, with various designs including computerized traction and suspension settings controls or mechanical suspension features, which are intended to reduce the lift and loss of traction of the front wheel under acceleration. Classes There is no universal authority defining the terminology of sport bikes or any other motorcycle classes. Legal definitions are limited by local jurisdiction, and race sanctioning bodies like the American Motorcyclist Association (AMA) and the Fédération Internationale de Motocyclisme (FIM) set rules that only apply to those who choose to participate in their competitions. Nonetheless, by present day standards in Europe, North America and the rest of the developed world, sport bikes are usually divided into three, four, or five rough categories, reflecting vaguely similar engine displacement, horsepower, price and intended use, with a good measure of subjective opinion and simplification. Marketing messages about a model from the manufacturer can diverge from the consensus of the motorcycling media and the public. Sometimes the classes used in motorcycle racing are