How aero tucks work for the pros on descents

From Bicycling.com

 

As the Tour de France heads into the mountains, we’re seeing some some unconventional descending positions, as riders aim to gain every second of free speed they can muster. Here’s what aerodynamic experts have to say about the pros’ super tucks, and some tips on refining your own.

“Cylinders. That’s what slows you down,” says Ingmar Jungnickel, aerodynamics R&D engineer for Specialized Bicycles. “Bike fitting is often focused on the rider’s back, but what we learned in the wind tunnel is that legs are 50 percent of your total drag.”

The quest to minimize drag from the body’s “cylinders”—legs, arms and head—has caused pro and elite racers to assume awkward aero positions on big descents, like Chris Froome’s famous top tube-sitting Stage 8 tuck at last year’s Tour de France.

“Everyone has two giant tree trunks going down to the frame,” explains Chris Yu, Specialized’s director of integrated technology. The idea is that “by sitting on the top tube, you’re bending your legs and reducing the height and surface area exposed to the wind, which cuts resistance and saves time.”

 

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