All the aero refinement isn’t worth anything if the athlete runs out of fuel or ends up on the side of the road with a flat. Reality dictates that most triathlon bikes have to be loaded up, especially for long-course races. “The goal is to achieve what we call a no-loss gain, basically riding with extra stuff [without adding drag],” says Specialized aerodynamics R&D engineer Chris Yu.
Smartly placing the necessities can keep your bike slippery in the wind. Even seemingly inconsequential details can have a major impact.
1. Pack behind the saddle. “Tucking stuff up extremely tight behind the saddle” is one way to achieve a no-loss gain, says Yu. “If you have a bottle, taping flat repair supplies to either side is an effective way to carry [them].”
2. Store between the arms. The gap between the aerobar extensions is also valuable real estate. A horizontal bottle between the arms is essentially invisible to the wind.
3. Hide your bag. “If you have a bike that’s not integrated on the front, tucking stuff behind the stem is typically a no-loss gain,” says Yu.
4. Fix your number. “Number placement is something a lot of triathletes can refine,” says Yu. Ironman and Ironman 70.3 races require athletes to wear their number for the bike in addition to the run. “A lot of the time you’ll spend a lot of money on a nice, tight tri suit and if you have a number flapping you’re negating a lot of the benefit of the race kit. That drag we have measured for a rider holding 40K per hour is something north of 5 watts. That kind of power savings, a lot of times, is the difference between a poorly fitting jersey and a nice, tight tri suit.” Tucking the entire number into the waistband or putting it over the stomach is against race rules, but securing the lower portion of the number is just as effective. “Tucking the edge in, wearing two number belts or Velcroing it to the suit is worth it.”
Mounting bottles to the frame typically comes with a speed penalty. “Whether it’s on the down tube or seat tube, [standard aero bottles] don’t make any of the bikes we’ve measured faster at all,” says Cervélo senior advanced research and design engineer Damon Rinard. “They always add drag.” (Some testing from the mid-’90s says otherwise, but those tests were conducted on round-tube bikes without a dummy.) While aero bottles such as the Bontrager Speed Bottle are not drag-free, they are better than round bottles. “Aero bottles are preferable to the round bottles in every case. On most frames—and it varies a bit—but when you add a round bottle to almost any aero bike, it adds about 50 grams of drag. An aero bottle creates about 25 grams of drag.” That difference is worth about 10 seconds over an Olympic-distance triathlon. In some cases, bottles designed for specific frames can have no aero penalty, but situating bottles behind the saddle or between the arms is almost always faster. Instead of bolting cages to the frame, invest in a rear-mounted or horizontal front bottle carrier.