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by Dave Rome
May 27, 2019
Photography by Swiss Side
In most situations, aerodynamic drag is the greatest force working against a cyclist. While much of that drag comes from the air pushing against the rider, it can also be from low pressure behind the rider.
Swiss Side, the Swiss-based aerodynamic wheel company perhaps best known for its partnership with DT Swiss wheels, has begun experimenting with pressure rakes, technology commonly used in F1 motorsport. Using what looks like an old TV antenna placed behind the bike and rider, Swiss Side hopes to gain a better understanding of how wind tunnel testing translates to the real world, and what knowledge can be gained through specifically measuring the swirling air behind a rider.
The pressure rakes provide Swiss Side with data points that paint a clearer picture about where gains might remain.
Swiss Side’s initial testing involved Ironman athletes Patrick Lange (two-time world champion) and Laura Philipp, and the use of two pressure rake systems. The first rake was used within the wind tunnel, attached to a robotic arm, and scanned the pressure fields at preset heights and distances behind and around the rider and bike. The second rake was attached directly to the back of Lange’s Canyon’s seatpost for use on a closed race track.
According to Swiss Side, “the measurements both confirmed the accuracy of the wind tunnel testing but also gave new insights into the areas where there is the most potential for reducing the aero drag and making Lange even faster.”
Jean-Paul Ballard, Swiss Side’s CEO, and former Head of Concept Design at the Sauber F1 racing team, said “The pressure rakes literally double our measurement capability in the wind tunnel and also allow us to make on-road measurements to ensure that the performance we measure in the wind tunnel and in CFD (Computational Fluid Dynamics), is delivered out on the road where it counts.”
A quick look at the video above raises a number of questions. How much of an impact is that huge box and wires attached to Lange’s bike having on the data? And does carrying so much weight up high impact Lange’s ability to hold the same position and produce the same power he normally would?
Triathlon and Ironman athletes are far less restricted by technical restrictions than road racers and it’s common for aerodynamic fairings or fuel storage to be implemented on bikes. Still, such research could reveal a number of unknowns that may be beneficial to road cyclists. Time will tell how useful this adapted technology proves to be.
Could this be a sign of where aero testing is headed?
Two-time Ironman World Champion Patrick Lange in the wind tunnel and in front of a large rake.
The on-road pressure rake is attached directly to the Canyon’s Speedmax CF SLX seatpost.
That’s a whole lot of mess. No doubt the guys at Swiss Side would have simulation data to isolate the effect of the instrumentation from the data they’re trying to capture.