A motorbike fairing is a housing placed on the frame of some motorbikes, particularly racing motorbikes and sport bikes, with the primary purpose of reducing air resistance. Secondary functions are to protect the rider from airborne hazards and wind-induced lowering of body temperature, and to protect engine components in the event of an accident. Motorbike windscreens are almost always integrated into the design of the fairing.
The main benefit of fitting fairings to sport touring and touring motorbikes is to reduce aerodynamic drag, thereby reducing fuel consumption and allowing higher speeds to be achieved at lower engine speeds, which in turn increases engine life.
A motorbike can have a front fairing, a rear fairing, a belly fairing, or any combination of these. Alternatively, a fairing can partially or completely enclose the entire motorbike, or even the rider.
The importance of streamlining was recognised as early as the 20th century, with some streamlining appearing on racing motorbikes as early as the 1920s. Although motorbikes usually have a much higher power-to-weight ratio than cars, motorbikes - and especially riders - are much less streamlined and aerodynamic drag has a very significant effect on the motorbike. Any reduction in a motorbike's drag coefficient will therefore result in an improvement in performance.
The term fairing appears in aircraft aerodynamics and is used to smooth airflow at the joints of components where airflow has been disrupted. Early streamlined designs were often unsuccessful and led to instability. Handlebar fairings, such as those on Harley-Davidson touring bikes, sometimes upset the balance of the motorbike and caused swaying.
Initially, fairings were covers fitted to the front of the motorbike, increasing the frontal area of the bike. Gradually, they became an integral part of the design. Modern fairings increase the frontal area by up to 5% compared to a bare bike. Fairings can carry headlights, instruments and other items. If the fairing is mounted on the frame, placing other equipment on the fairing reduces the weight and rotational inertia of the steering unit and improves handling.
The BMW R100RS, produced between 1976 and 1984, was the first mass-market sportbike to have a full fairing as standard and marked the beginning of the widespread adoption of fairings on sport and touring bikes.