Sport bikes emphasize top speed, acceleration, braking, handling and grip on paved roads, typically at the expense of comfort and fuel economy in comparison to less specialized motorcycles. Because of this, there are certain design elements that most motorcycles of this type will share. Sport bikes have comparatively high performance engines resting inside a lightweight frame. Inline-four enginesdominate the sport bike category, with V-twins having a significant presence, and nearly every other engine configuration appearing in small numbers at one time or another The combination of these elements helps maintain structural integrity and chassis rigidity Braking systems combine higher performance brake pads and multi-piston calipers that clamp onto oversized vented rotors. Suspension systems are advanced in terms of adjustments and materials for increased stability and durability Most sport bikes have fairings, often completely enclosing the engine, and windscreens that effectively deflect the air at very high speeds, or at least reduce overall drag.
Sport bikes have high footpegs that position the legs closer to the body to improve ground clearance when cornering, and a long reach to the hand controls, which positions the body and center of gravity forward, above the fuel tank. The rider leans forward into the wind, the force of which can comfortably support the rider's weight at speeds near 100 mph (160 km/h), but at lower speeds leaves too much weight on the arms and wrists, causing fatigue.
Streetfighters are derived from sport bikes, originally being customized sport bikes with the fairings removed and higher handlebars replacing the low clip-on handlebars. Since the 1990s, factory streetfighters have been produced. As with naked bike and muscle bike (below), the name streetfighter is used to help clarify the middle ground occupied by designs that blend elements of both sport bikes and standards.