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Secrets Of The Wind Tunnel

  • By Jesse Thomas
  • Published Jul 17, 2014

The surprising place Jesse Thomas found his biggest aero savings.

I woke buzzing with excitement on a late January morning. I was about to take my first visit to the “Win Tunnel” at Specialized HQ in Morgan Hill, Calif. The Win Tunnel was designed from the ground up by Specialized aerodynamicists and product designers Mark Cote and Chris Yu, and is an incredible tool for Specialized athletes. Unlike testing anywhere else, I wouldn’t have to pay $500 or more an hour to rent time. I’d have the whole day to myself, which meant lots of time to test my position, check a bunch of equipment options and just hang out with some good dudes. It was going to be an awesome day.

Upon my arrival, I went through the schedule with the Specialized team. First, we’d test some wheels, then some helmets, a few position changes, and finally racing suits. We started cranking, one test at a time. We first discovered that my Rolf Prima TDF6’s (tubular) were a few watts faster than the Ares 6’s (clincher). We also discovered that the disc cover that I use was surprisingly similar to a full disc. Good to know!

Next we tested helmets, and for me, the Specialized Evade (short aero helmet) was almost identical to the TT2 (long aero helmet). In fact, in a crosswind, it was a couple of watts faster. Lighter, faster, more breathable, done!

Then we tested my “praying mantis” arm position versus a more typical “flat” arm position. As it turns out, it was about 5 watts faster for me to ride mantis style, which was surprising to Mark because that wasn’t the case for most of the other riders he’d tested. So while I might suffer on goofiness points, the mantis would stay.

After a few more position changes that revealed little to nothing, we eventually got to the suits and found the biggest difference of the day. My new Pearl Izumi sleeved suit with a more aerodynamic material was 8 watts faster than the traditional sleeveless suit I’d raced with the year before. Awesome to know—another big benefit found.

I was pretty happy with the day when we took a break for a late lunch. Now that the “work” was over, we had a little bit of time left for some pictures and videos. Outside of making me faster, one of the benefits of going to the tunnel for my sponsors are the media opportunities: cool videos, pictures, etc. Wind tunnel pics look super badass and get lots of good press and social media attention.

But I hadn’t taken any pictures that morning because I realized upon arrival that my legs weren’t shaved. This is typical for me, as my wife Lauren prefers I keep it Austin Powers-style when possible. So I only shave my legs for races and photo ops, because it feels faster and most of my sponsors don’t want pictures of Bigfoot on their websites.

So as we were chatted at lunch I said to the guys, “If it’s all right, I’d like to get some pics for sponsors and stuff. But I forgot to shave my legs this morning.” Silence. I continue, “And since we’ve got time and I need to do it anyway, why don’t we test shaved legs and see if it makes a difference? It’ll be funny, and we can answer that age-old question every cyclist debates of whether it’s actually any faster or not.”

RELATED: Specialized Constructs Fully Functional Wind Tunnel

Mark instantly agreed. He’d always figured it made a watt or two of difference, but had never heard of anyone actually testing it before. It’s the type of stuff you can only pull when you have your own freaking wind tunnel at your disposal.

So after a hearty lunch and our work behind us, we took a baseline test. Then, at Mark’s request, and since it was all a joke anyway, we turned on some music full blast for the leg-shaving ceremony (see the photos below). To start, I requested “Holding out for a Hero” by Bonnie Tyler as featured from the ’80s BMX movie “RAD.” It seemed appropriate. For the next 20 minutes, we six dudes listened to ’80s hits while I shaved my mammoth trunks, taking pictures along the way. It was maybe the most ridiculous and awesome thing ever to happen in a wind tunnel. Eventually, I got back on the bike, the guys got in the control room, and it was time to go.

All the previous tests were performed in 60-second chunks: The wind would start, then a countdown, then 60 seconds of data holding your position, then the wind stops and you’re done. Every once in a while Mark and Chris would run two or three 60-second tests in a row, just to make sure the data was consistent.

So I got on the bike, the wind fired up, the countdown began and 60 seconds went by. But instead of the wind stopping, it kept going. Then another countdown, and another 60-second test. Then another, and another, and another, and another. Six 60-second tests went by; I wondered what the hell Mark was doing. Is he playing a trick on me? I’m starting to get tired, and it’s cold in the wind tunnel in January!

Finally the wind stops; I hop off the bike and enter the control room. The mood is kind of creepy, the exact opposite of our ’80s party just a few minutes ago. Everyone is silent and I see Mark staring blankly at the computer screen. Eventually, I say “Ha, that was fun. What did we discover? One watt? Two watts?”

Mark doesn’t even look at me. He just stares into the screen and says, “No. It’s impossible. It can’t be.” I feel like Marty McFly in “Back to the Future” witnessing Dr. Emmett Brown’s “1.21 gigawatts” tirade. Eventually I say, “Mark, what’s the deal? Did it do anything? You’re kind of creeping me out, dude.”

Finally he looks up from his computer screen and says with absolute conviction, “15 watts.”

I just start laughing, “That’s funny. Haha. Yep. I’m a hairy dude. I get it. But seriously, what happened?”

“Seriously. It was 15 watts faster. I can’t explain it. I can’t believe it. That’s why I ran so many samples. But that’s what it’s saying—15 watts for your shaved legs.”

In the case that this test was some kind of miscalculation or my legs are just freakishly hairy, we waited to tell the story until Mark and Chris had some time to corroborate the data. As it turns out, Mark has now tested five other individuals and seen drag savings of anywhere from 7 to 13 watts depending on where they rank on the 10-point “Chewbacca Scale” he created (seriously). Since the other riders scored only 5 to 8 on the Chew-scale (I was the only 9), a slightly lower drag reduction was expected. Yes, my legs are freakishly hairy, but the calculations were correct.

So there you have it—the secrets of my day at the wind tunnel. I saved 2–3 watts on my helmet and wheels, 5 watts with my arm position, 8 watts with my new kit. But the big winner was the 15 watts I saved by clear-cutting the forest off my lower legs.

Pro triathlete Jesse Thomas is a four-time Wildflower champion and the CEO of Picky Bars. More “Triathlife” from Thomas.

 

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