Each of us riding on a group ride understands that tucking in behind someone saves energy. Magnify the number of people involved in a tightly formed 120 person peloton and the advantage goes up exponentially. Until recently, no one had, apparently, ever calculated how much of an advantage it actually is.
If you’ve never thought about it, consider that the average Tour de France rider spends about 80 racing hours tucked within the peloton over the course of the competition. That’s eighty hours looking forward seeing the same array of the backsides of all those ahead of you, hemmed in by all those beside you and behind you while being swept along in mass. How much energy are they actually saving?
According to a new study in the Journal of Wind Engineering and Industrial Aerodynamics, cyclists riding in the heart of the peloton have 95% less drag than they would experience riding alone. Wow! And they are not even riding an e-bike! Of course, without knowing the precise calculations, cycling teams have used the peloton to save energy for team members to use on climbs, sprints and attacks.
The most advantageous location in the peloton is in the middle and at the rear. According to the authors of the study, riders in those locations would experience less than 10% of the wind. Translation for us non-engineering types: a solo rider at the same effort would be capable of only 25–33% of the peloton’s speed. These calculations have replaced the generally accepted calculations from wind tunnel testing that the energy savings was merely in the range of 50 to 70%.
They pointed out that while receiving all the advantages of being in the middle of the peloton, the riders have several distinct disadvantages: they can become trapped, they can’t see ahead, they are not aware of obstacles on the roadway, and when the unexpected occurs big numbers of them hit the ground.
As a side note, it took 18 months to complete the study because of the immense number of computer calculations necessary. Apparently to do this, a 121 rider simulation involved some 3 billion calculation points, right down to the 1 mm pocket of air that surrounds each cyclist.
Source: Wall Street Journal, Joshua Robinson, July 25, 2018