The first test measured the aerodynamic drag of each combination in the A2 Wind Tunnel. Both road positions were identical and both triathlon positions were also identical.
The graph shows the drag differences between the bikes and positions tested in the conditions (see Fig. 1 below). The wind sees the bike, components and rider as one complete system, so the drag savings cannot be attributed solely to the differences in position or equipment.
The results show that the standard road bike and position has dramatically more aerodynamic drag than the aero road bike and road position. The difference between the two triathlon-position setups, however, is much smaller.
Data collected in the wind tunnel provides reliable information, but triathlons aren’t contested in a wind tunnel. To measure how these aerodynamic differences translate to speed when riding on a road, I conducted a riding test on two Nascar tracks. The cyclist rode at a specific power level over an identical course in all conditions and I measured his average speed. These tests were run several times over several months under varying conditions, and the data was averaged for the results below. In the end, the graph shows the results to be on par with the tunnel testing (See Fig. 2 below).
This test indicates that there are major differences in speed between the aero road bike and the standard road bike, even though the rider was in the same position. There is also a large difference between the aero road bike ridden in a road position and an aero road bike ridden in a triathlon position. The difference between the aero road bike ridden in a triathlon position and the triathlon bike, however, is very small.
So, can an aero road bike double as both a fun-riding road bike and a no-compromises triathlon bike? The tests I conducted show an aero road bike provides aerodynamic performance similar to a pure triathlon bike, but still creates slightly more wind drag. If you are trying to squeeze out every advantage, an aero road bike is not an equal substitute for a triathlon-specific bike. However, for those looking to have just one bike for every style of riding and racing, an aerodynamic road bike is definitely the best option.
Special thanks to Zipp, Blue Competition, Shimano, Hed, FSA, Litespeed, Specialized, Oval Concepts, North Wilkesboro Speedway, Charlotte Motor Speedway and A2 Wind tunnel for their assistance and support of this project.