As the bicycle specialist at the A2 Wind Tunnel (Editor’s note: Giraud has since left A2 and now works with Blue Competition Cycles, rideblue.com) in Mooresville, N.C., I repeatedly see that a dedicated triathlon bike generates significantly less aerodynamic drag than a traditional road bike, but that performance benefit comes with a sacrifice. Tri bikes are not well suited to riding in a group of cyclists or on sketchy roads, so an athlete either has to own two bikes or compromise between race-day speed and training-day functionality.
Written by: Mike Giraud
A new generation of road bike has emerged with aerodynamic tubes, a design feature that is typically reserved for triathlon bikes. The idea behind this style of bike is to combine the functionality of a road bike with the straight-line speed of a triathlon bike. If you are looking for an all-purpose bike that is equally suited to a Saturday morning group ride and a Sunday morning triathlon, this new generation of road bike might be the answer. These bikes ride just like a typical road bike but the question is: How much aerodynamic performance do these aero road bikes sacrifice compared to a truly dedicated triathlon bike?
To answer that question, I compared the aerodynamic drag of four different bike-and-rider setups. The bike itself generates a significant amount of aerodynamic drag, but the rider’s body creates most of the wind resistance, and a key difference between road and tri bikes is the geometry. Triathlon geometry helps a rider achieve an aerodynamic and comfortable position, so I tested both road and triathlon-style positions. The bike-and-rider combinations I tested were:
1. Traditional road bike with standard road components with a rider in a road position and a standard cycling kit.
2. Aero road bike, moderate aero components, road position and a standard cycling kit.
3. Aero road bike, extreme aero components, triathlon position and a skinsuit.
4. Aero road bike (TT build), extreme aero components, triathlon position and a skinsuit.
5. Time trial bike with extreme aero components, clothing and position.