A Day at the Wind Tunnel with Clara Brown

Tips, insights, and the endless pursuit of saving 7-10 watts

^{By Clara Brown}

Clara Brown is a two-time World Champion, a six-time World Championship medalist, and a Tokyo Paralympian. She lives and trains near Portland, Maine, with her teammate, coach, and partner, Noah Middlestaedt. Off the bike, she advocates for greater inclusivity and leadership roles for athletes with physical impairments. For more insight into her story, check out her film ABILITY

When I got the chance to spend a day at a wind tunnel to hone my time trial position and aero equipment, I was nothing short of giddy upon arrival, and that feeling lasted all day long. I honestly cannot recall any other day in my career - beyond racing itself - that has been as informative and eye-opening as my day at the A2 Wind Tunnel just outside of Charlotte, North Carolina.

Life as a pro cyclist certainly comes with many perks, including opportunities and resources that are not necessarily accessible to the public. For better or worse, it is imperative to pursue every possible and legal marginal gain when competing at the very top of the sport. Moreover, a medal-contending performance, particularly in individually timed events, is becoming more and more challenging for those who do not utilize vast amounts of data to eke out every saved watt from every facet for both the bike and the rider.

With this being my first experience at a wind tunnel, I was unsure of what to expect and how to best use the precious time in it. Two US Paracycling teammates joined me, so the three of us each planned to take a block of time for testing our specific equipment and positions. We'd also have the generous help of our good pal and coach Geoff, who kept us sorted and offered an extra set of hands (especially since two of us are deficient in that regard).  

We each put a lot of thought into what exactly we wanted to test in the tunnel and the order in which we were going to test it. This helped us be more time-efficient and well-organized, which was vital since time in the tunnel isn't exactly cheap. The biggest tip I can provide to make your day run smoothly and save you money in the wind tunnels is to treat your session as though it is a race day. Have your numbers pinned ahead of time if you are comparing a number pocket versus pinned number. Make sure your helmet straps are properly adjusted if you borrow helmets from the wind tunnel's vast inventory. And have tools and parts laid out, ready to be swapped quickly between each test period. Of course, if we’re talking about generally being as prepared as possible, I must note that you cannot forget snacks. Ice cream is an obvious choice.

The A2 Wind Tunnel facility is truly mind-blowing, no pun intended. The tunnel is roughly 25 meters long and shaped like a slide-less trombone from the exterior. Inside, four gigantic fans at the back will suck air from the front of the tunnel over the rider to yield their CdA (coefficient of aerodynamic drag). At the front end, there is a slightly raised platform with a bike mount that can swivel to determine a rider's CdA at various yaw angles.

The 'control room' has several monitors that display live camera angles from inside the tunnel, showing the rider from above, from many angles at each side, and from the front or back. There's also a central computer system in the control room operated by a staff member, which has all of the data points from each iteration tested. These data are then organized into a spreadsheet shared with you at the end of your session for easy reference. We each provided our approximate average race speed, which can have a huge effect on the aerodynamic property of any given piece of equipment or position. For context, imagine the discrepancy between my road time trial speed and my former World Champion teammate's track kilo speed. Hint: it is substantial. Once everything was set up and I actually started testing, the novelty of what I was doing really set in.

One of my favorite parts of the day was watching both of my teammates test and following their results in real-time. We all came in with our assumptions and predictions, and it was thrilling - and in some cases heartbreaking - to see most of our preconceived notions shattered once numbers told us the real story. All of us did considerable research before selecting our equipment over the years based on information that was available to us, whether it was wind tunnel data from other riders publicly shared online, manufacturer's official data, and analysis of our personal positions by applying widely accepted aerodynamic principles to our fits.

One of the greatest takeaways from the day was realizing that just because something is marketed, priced, or hyped as the 'fastest' product out there does not necessarily mean it will be the fastest on you. With three distinctive riders, we were able to compare equipment such as skinsuits, shoe covers, and helmets across a wide range of speeds and positions. Skinsuits, we found, were the most rider-specific. One particular suit was far and away the slowest on one of us by nearly 20 watts, which is quite an enormous margin, but it was within a few watts of two other suits on a different rider. 

On the other hand, helmets were the most similar and universal across riders and positions. We were delighted to see that the two Lazer helmet models we tested, Victor and Volante, were both stand-outs across three riders and four positions (three time trial positions and one track mass start position). It was incredibly validating to see our individual and collective data confirm that we made the right call about at least one of our equipment choices for the Tokyo Paralympic Games this past summer. Not only does Lazer make some of the helmets with the best protection ratings on the market, but damn, they are slippery too.

Of course, it is easy to see this plethora of information at the end of the day and get carried away with extrapolating, hence the heartbreak I mentioned earlier when assumptions and predictions are shattered. All three of us had moments of thinking, “If I had known this piece of equipment or position were faster by x-number of watts, that would have translated to saving this much time, and therefore made my result x-much better.” But, we also took solace in the fact that we had previously selected equipment based on the best resources we had available to us at the time. Now, moving forward, we'll have the confidence that our decisions are even better informed given the concrete data we collected, which hopefully translates to more success on the bike.

Knowing firsthand the immense value of wind tunnel testing, I am eager to keep fine-tuning my setup and seeking out further watt savings in seasons to come. The one constant, though, is that a Lazer helmet will be on my head, smoothing out my wild mane of red curls into a sleek bullet that punches a tiny hole through the air.

Follow along with Clara’s bike racing adventures on Instagram @clara.brownie & @gimpcyclist