The chest fairing may go down in history as the most fleeting invention that cycling has ever known, more seen and unseen even than long socks or jerseys embossed to generate aerodynamic vortices. Even before its massive popularization, the International Cycling Union (UCI), always trying to abort any innovation, has put a stop to it. He did it through the Itzulia commissioners, who on April 1, in the Irun time trial, warned the teams: it is prohibited to wrap the radio station device in plastic or any other element to increase its volume when carries on the chest. “So we didn’t use it, because the station needed protection from humidity or rain,” explains Jon Iriberri, biomechanic at Visma. “We couldn’t even make a minor fairing by placing the radio held by the heart rate monitor tape…”
On Tuesday, July 18, 2023, Jonas Vingegaard decided the Tour de France in his favor in the shadow of Mont Blanc, beating Tadej Pogacar by 1m 38s in a time trial of only 22.4 kilometers. The exceptional result — “the best time trial in history”, according to former cyclist Tom Dumoulin, the Indurain of the 21st century –, of an almost unknown, stratospheric magnitude, was greeted in the media by more skeptical than laudatory articles.
How is it possible that Vingegaard is able to get four and a half seconds per kilometer out of Pogacar, a unique talent, a magnificent time trialist? It was the most repeated question, and the only answers found – the cold sore that betrayed a state of sickness. form in Slovenian, for example—they could only partially bury the doubts. Although aerodynamic considerations – the smaller size of the Dane, its better fit to the bicycle, the supposedly more refined material of the Cervélo Jumbo bikes compared to the Colnago of the UAE – were also taken into account, even in a generic way, to test how with a deployment not very different in watts there could be so much difference in result, so much Danish efficiency, little attention was paid to the value of one element, one more grain of sand in the sum, which was then barely mentioned: the considerable bulk that the radio station surrounded by several layers of voluminous insulating wrapping formed in the Dane’s chest, a keel purposely placed there, in the front and in the chest, not in the belly, in order to eliminate turbulence and increase its coefficient of aerodynamic penetration.
In no time, Vingegaard, also physically scrawny, became a Fausto Coppi, a legend called Il Airone, The Heronboth for his very long legs born from an infinite femur, the bone whose length is directly related to cycling talent, and for his keel-shaped chest that cut through the air.
The pectoral fairing was not invented by Jumbo or Vingegaard, but comes from triathlon, like so many cycling advances, starting with the handlebars of time trials. A month later, at the Glasgow Time Trial World Championships, Remco Evenepoel sported a similar chest during the almost 50 kilometer course at almost 52 per hour on average. He achieved victory with a 12s advantage over the Italian Filippo Ganna. “Of course it makes sense,” says Iván Velasco, design engineer, specialist in aerodynamics, at Movistar. “All the teams wear the radio on their chest to try to create a little fairing. We have tested it a long time ago and we have seen that it gives a clear advantage in a time trial position.”
Although the winning team of the last two Tours, now called Visma, has been resorting to its benefits for more than a year, only this week, almost nine months after D-Day, a study has quantified its contribution with some precision, up to one second per kilometer in a 25 kilometer time trial. That is, about 22s of the 98s with which Vingegaard overwhelmed Pogacar is due to the radio station in his chest. This calculation emerges from the comparative study carried out with a mannequin and complicated computational calculations of fluid mechanics in the Eindhoven wind tunnel by engineer Bert Blocken, from the University of Edinburgh. Blocken calculated positive and negative pressures and turbulence with different sizes of packages and in different positions and concluded that with the most advantageous one (a prismatic shape 31 centimeters wide and nine centimeters high), at a speed of 15 meters per second (54 kilometers per hour), the advantage over whoever was not wearing a chest fairing would be 19.5 seconds in a 25 kilometer time trial. The slower the speed, the greater the benefit. The Tour de Vingegaard time trial was shorter, 22 kilometers, and given its difficulty, much slower. He won it at 41 on average (11.45 m/s), which allows us to infer an advantage of up to one second per kilometer. “But this is a frankly optimistic calculation,” says Iriberri with some regret given that, once again, ordinances and regulations oppose the natural desire of every technician to take advantage of technology and science to achieve maximum performance. “The wind tunnel always gives more, but the fairing does offer an advantage.”
The computer calculations of engineer Blocken, who actively collaborates with Visma and discovered that very bulky objects placed behind the cyclists also push them, reducing the tail turbulence that slows them down, is thus behind the usual practice of the teams of doing follow with a car loaded on its roof full of bicycles its best runners in the time trials, which always allows them to gain seconds. His studies also support the bizarre helmet that Visma debuted this March and that caused a crisis in the UCI’s department of fighting technological fraud. Its manager, the former Australian cyclist Mick Rogers, wanted to ban this model, and the balaclava used in the Soudal and the Bora under the helmet, considering that they did not fulfill their only mission, that of protecting the head in falls. The bicycle and components industry managed to get the UCI to back down. Rogers was forced to resign. He has been replaced by the American Nicholas Raudenski, a police officer with zero experience in cycling who comes from the fight against financial corruption in football and illegal betting. And, given that the pectoral fairing cannot be established as a business area for the industry, it seems difficult for him to advocate pardoning it from the ban already issued.
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