Triathlon bars or aerobars include various styles of aerodynamic handlebars for racing bicycles and particularly time trial bicycles. Included are narrow, bolt-on extensions that draw the body forward into a tucked position, pursuit bars that spread the arms of the rider but drops the torso into a slightly lower position, and integrated units that combine elements of both designs.
Triathlon bars are commonly used in triathlons and time trial events on road and track. However, they are illegal in most mass start road races or any other event where drafting is permitted because, while aerodynamically advantageous, they tend to draw the hands away from brakes, make the rider slightly more unstable on the bike, and can be dangerous in the event of an accident. Further, they are not useful in sprints or shorter climbs where power is of greater importance than aerodynamics.
Specialized shift levers (known as bar-end shifters) do exist that can be installed on some triathlon bars so that they can be reached without moving the hands from the aerodynamic position. The complementary brake levers in this handlebar configuration are placed in the ends of the accompanying pursuit bars.
Aero bars are a recent addition to road racing time trials, with Greg LeMond first using them in the 1989 Tour de France. In a controversial time trial on the final day, LeMond used them to beat yellow jersey wearer Laurent Fignon by 58 seconds, changing a 50 second deficit into an 8 second lead. Fignon protested at the use of these bars but was unsuccessful.