an aerodynamic advantage as well as more power when in the "aero" position. Empfield's bike had 650c wheels and an 80 degree seat angle which was unique to the period. Many professional triathletes were sceptical of the "steep" design at first but when Ray Browning rode it at Ironman New Zealand breaking the bike and overall course records and left the bike leg with a 30-minute lead over rival Scott Tinley, the concepts were here to stay. The aerodynamic shape causes somewhat higher weight, even if carbon fiber is used. In very hilly races where a lot of time is spent in slow uphills, a low-weight traditional road bicycle might be preferred. Aerobars Aerobars, also commonly referred to as "tri-bars," are handlebars designed to reduce the cyclist's wind profile. Triathlon played a key role in the development of cycling with an aero geometry during the 1980s. Aerobars are used in other forms of cycling, such as time trials and some events in track cycling. Instead of the familiar curved "drop bars" of road bicycles, aerobars are mounted to a set of "pace bars" or "bull-horns". A pair of bars stretches straight forward from the centre of these handlebars at the stem of the fork. Padded cups or pads in the middle of the bars support the athlete's elbows and/or forearms while the hands are stretched forward to hold the centre bars. This position keeps the rider's elbows in close to the body and lowers his or her torso compared to the usual upright position. The brake levers are mounted on the side horns; the rider will hold these instead of the centre bars when braking or manoeuvring is required. Often the shifters for the derailleur gears are mounted at the tips of the aero bars allowing the athlete to change gear ratios without compromising their aerodynamic position. Riding with aerobars is facilitated by adopting a steep seat-tube angle, often referred to as an "aggressive" geometry. The forward nature of this positioning is not as easy to control as traditional seat tube angle and upright position. Manoeuvrability is compromised for an aerodynamic body position when a bike is fitted with low aerobars. The International Triathlon Union regulates the size of aerobars used in competition for draft-legal races. Triathlons allowing drafting promote cycling as a group on the cycle leg of the triathlon, allowing athletes to compete with a very aggressive geometry