Specialized Bicycles Builds The First Cycling-Specific Wind Tunnel

A crazy new tool for testing biodynamics and aerodynamics might change the bike production game

What this team has accomplished is impressive enough to excuse a little awkward Photoshopping.     Photo: Courtesy of Specialized

The beginnings of the wind tunnel.

The Specialized wind tunnel is optimized for humans and can accommodate multiple riders at once.

The wind tunnel under construction.

The interior of a Specialized wind tunnel turbine.

Specialized is now the only bike company that can test everything they make themselves.

Drag is the single biggest force affecting a cyclist—eliminating every bit you can is critically important if you want to save energy and move as quickly as possible.

Traditionally, cycling companies test their highest end product for their most valued racers in hour slots that can cost thousands of dollars per day, in wind tunnels scattered across the world. Wind tunnel testing helps teach manufacturers and racers where drag occurs and lets them experiment with reducing it.

But wind tunnels aren’t built for testing relatively slow speed bikes. They’re built for Formula One racecars and even spaceships. Bike nerds have adapted these tunnels to run tests on significantly smaller two-wheeled pedal-powered machines—but a bike is a not a car. It’s not the same shape, nor does it go the same speeds.

So Specialized designed and built a wind tunnel just for cycling. It’s optimized for humans, not cars, so it can test with more accurate and precise conditions that are more representative of bike speed. The size and shape of the tunnel lets Specialized test multiple riders at once, which will help the company better understand how different crosswind angles affect individuals in a group of riders. 

With a wind tunnel on-site, Specialized R&D can literally dream up an idea one afternoon, and test it the next. A Monday morning flash of brilliance can be CAD’d by the lunch ride, rapid prototyped by Tuesday, tested in the tunnel Tuesday afternoon, with a working prototype ready for the Wednesday lunch ride. With an on-site wind facility, Specialized will be the only bike company that can test everything they make--from a commuting helmet to an aero helmet—and it will be able to develop an in-depth understanding of every aspect of rider position for every kind of rider, from competitive racers to every-day commuters.

The most valuable aero testing results don’t just happen in the tunnel, however. Wind tunnel data must be gathered and interpreted and checked against data from computational fluid dynamics (CFD) and a new on-road Data Acquisition System developed by Specialized (DAS) to best understand how a bike, helmet or racer will perform in the real world. Specialized’s DAS can wirelessly transmit data instantaneously from anywhere in the world back to Specialized HQ in Morgan Hill, California, for evaluation and feedback. DAS is a fine-tuned recording machine. It captures power, speed, rider position and the direction of wind as it hits the rider—so that engineers back at home base can measure the true coefficient of drag on a rider.

CFD lets aerodynamicists play in virtual space with a range of shapes and surfaces, simulating the flow of various fluids across those shapes to test their aerodynamic performance. CFD allows an engineer to see, through simulation, things he can’t see in the real world, like tiny ‘bits’ of drag on a frcame, some as small and seemingly insignificant as a paperclip. It’s let engineers predict aero behaviors, discard design duds before prototyping, or modify shapes that have already been wind tunnel tested.

Data needs to be interpreted, so Specialized has put together a top team to do that. In-house aero aficionados, Chris Yu, Mark Cote, Chris D’Aluisio, and Chuck Teixeira, have 50 years of aero experience between them and over 20,000 hours in wind tunnels. Yu is a Doctoral candidate in High Fidelity Flow Simulation. Mechanical engineer Cote, “The Aero Pharaoh,” spent four years running the wind tunnel at MIT as an undergrad, then spent countless hours in seven other facilities after. Teixera, one of the first to be part of wind tunnel testing in the 1980s, is an aero wheel expert. D’Aluisio has been developing bikes since 2000, and is the rider-R&D liaison. They all helped Specialized deign and build its new facility.

This team interprets wind tunnel and DAS data, and they use it to advise the Body Geometry Fit team, Specialized Racing staff, and athletes on changes that will improve their performance. For a racer—it means that they’ll learn how to be faster and get the gear to enable that effort. For a commuter, it might mean that the water splashing off their fender won’t splash onto them, or that their helmet won’t whistle when the brakes are off and they’re throttling downhill.

Specialized has already scheduled tunnel time with downhiller Aaron Gwinn and triathlete Craig Alexander. Biomechanics and aerodynamics in one space, improved product for all riders, evolved understanding of how to sit on and pedal a bike. It’s just one more step in Specialized’s quest for two-wheeled world domination.

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