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The Torqued Wrench: Aero is everywhere

  • By Caley Fretz
  • Published Apr. 25, 2012
  • Updated Apr. 26, 2012 at 12:35 PM EDT
Wind tunnel testing yields solid aerodynamic data, but can't account for real-world variables

No perfect solution

“Anything that you do, you need to have the appropriate protocol for testing,” says Mike Giraud, aerodynamicist with Blue bicycles and former head of the A2 wind tunnel in North Carolina. That sentiment seems to be a running theme with aero testing: While there are many ways to do it well, far more exist to do it poorly. Aerodynamicists have to take a close look at what they are hoping to gain out of a given test, which variables they can control, and which they can’t include at all.

There has to be an understanding, too, that no test is perfect. Wind tunnel testing will indeed provide an accurate and repeatable drag figure for a piece of equipment. But the tunnel can’t tell the story of interaction with all the variables found in the real world. Likewise, real-world testing can’t control all the necessary variables, making it inherently less accurate and repeatable.

Aerodynamicists must weigh these two weaknesses, and apply the correct testing methods accordingly. “Field testing has no real place in (the equipment) arena until you are down to the very end and looking to tests the products under an athlete in the real world,” says Giraud. “The truth is at this point, 99% of all your work is done, and this becomes more confirmation than anything else.”

And protocol is vital. “Your test athlete cannot also be your control athlete because every time you make a change to your test athlete, you’ve now changed your control,” says Giraud. “Having a control rider able to record all of those variables is one step closer to getting descent results.” In other words, as changes are made to a rider’s position or equipment, external variables might be changing as well. Doing the testing with a second rider, who never changes position or equipment, helps remove those variables.

Though the methods currently available may be imperfect in and of themselves, their combination does paint a highly accurate picture of the wind’s interaction with riders and their equipment. The data available (particularly third-party data like that found in our own Velo Magazine reviews) can be relied on as relatively accurate representations of the gains you will actually see in the real world. One thing is certain however: Riders not already on the aero bandwagon are only slowing themselves down.

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FILED UNDER: Bikes and Tech / The Torqued Wrench TAGS: /

Caley Fretz

Caley Fretz

Tech Editor Caley Fretz came on board with VN in September 2010, and now splits his year between Boulder, Colorado and Annecy, France. Beyond his journalistic pursuits, he is a category 1 road, 'cross and track racer. He also holds a pro XC mountain bike license, though unlicensed racing is now more his style.

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