We’ve all read the reports over the winter – big name Grand Tour riders hunkering into a wind tunnel to study, adjust, and perfect their time trial positions… translating to much faster times on the road. PEZ may not have any Grand Tour aspirants, but we figured there was plenty to learn from some tunnel time of our own under the guidance of wind/tech-maestro Mike Giraud.
I’ve often wondered about those wind tunnel excursions that every superstar seems to make to eke out that last little bit of time in a time trial – and how much could some tunnel time of my own improve my TT position?
My questions were recently answered as I booked in for a few hours with Mike Giraud at the A2 Wind Tunnel in Mooresville, North Carolina in early March.
If you’re not a NASCAR fan or aren’t from the South, Mooresville doesn’t mean too terribly much, but to everyone else: this is NASCAR country, and the drive to the wind tunnel proved just that as I turned onto Route 3 – that’s Dale Earnhardt’s road, Big E.
Yeah, that’s nice. Bikes are fast, cars…much faster. A2 is well established among the good ol’ boys of Nascar.
Banks of computer screens report back all kinds of data.
When you first enter, you head in toward the control center and some very nice looking computers with lots of numbers and whatnot that meant absolutely nothing to me when I walked in the door, but a whole heckuva lot more when I left. And now, I’ll forever be wondering about my coefficient of drag when I’m on the bike…even when I’m in a normal crit or road race it pops into my mind. You know what they say about knowledge…
I’ll let the A2 boys take it from here for the technical nitty gritty on just how this bad boy works:
“A2 is capable of testing up to 85 mph, while allowing aero force calculations for virtually any speed by scaling the force data with fundamental aerodynamic calculations. Our tunnel utilizes a passive boundary layer system and an adaptable ceiling in order to make A2 an incredibly versatile wind tunnel, capable of testing many different types/styles of vehicles. We want to break the mold of expensive wind tunnel testing, and help educate racers who thought wind tunnel testing could never be possible for them.”
In 2007 a new system was developed for testing bicycles in the A2 wind tunnel. A separate data collection system was added specifically for aerodynamic testing of the cyclist community. Also added was a digital video camera system (front, side, top) to give the riders a better understanding of what is happening with their position through the use of video playback and image overlays to see these changes. A separate platform was developed that allows spinning wheels (front/rear), ± 25 degrees yaw capability and is also integrated with a Computrainer® in order to give the rider realistic feedback. You can visit the website for more specific information about the bicycle testing program.
Walking into the wind tunnel’s housing area is an experience in itself – it’s huge, and the peculiarly shaped tunnel definitely beckons you inside for a closer look. I had never seen anything like it before, and I’m guessing I won’t come across anything like it in the foreseeable future either.
If the A2 Windtunnel is good enough for George Hincapie, it’s good enough for me.
Down To The Real Work
Just visiting the wind tunnel would be very cool, but I was here to get on the bike and see just how ‘aero’ I am. The first thing Mike did was take some basic measurements from my bike to use as our base lines. He also did me the big favor of hooking me up with some aero wheels for the testing.
My initial position on the bike was fairly simple – somewhat upright, arms a bit wide apart. It seems to work for Millar and Wiggins, why not me, right? Absolutely not is the correct answer here…which I found out fairly quickly.
Mike told me that on the bike, your body makes up for 80% of the drag, which makes perfectly good sense that my body would cause a bit more drag on the air flowing over me than the tiny bike and wheels that I’m riding.
With this in mind, it becomes apparent just how much performance can be gained by working on my body position. People are willing to shell out thousands to whittle off a few seconds here and there via a disc, or tri-spoke, or TT bike, but a proper, fast as humanly possible position for your own body type will make those seconds you can buy with equipment look embarrassingly small. Mike mentioned two vital components that should come before that new TT bike and wheels (with aero bars being the permanent #1 must): aero helmet and skinsuit. Of course, when he said this, I blushed a bit, because I had neither.
Our starting point – wide bars and wide hands.
How low can we go…? Let’s find out.
The front end of my bike would be the focus of today’s work. How could we eke out as much of an aerodynamic advantage as possible? How tight and low could I go before I went too far? There is obviously a limit, and once you cross that, it doesn’t matter you aerodynamic you are if you can’t pedal hard.
The short answer to all of this? Bring the elbows as close together as possible and drop the bars. That sounds easy, but there was a lot of work to be done to find out exactly how close, exactly how low.
We did at least 15 different set-ups. Each time, Mike came in, made an adjustment, told me to get ready, and then VRAAAAAAAM! the fans turned on, the air blew cold and fast (do NOT forget your sunglasses), and I tried to pedal as evenly as possible and move as little as possible to help get the most accurate reading – the pedaling sections of the day were definitely not more than a minute, but probably around the 30-45 second mark, and yes, they do begin to wear on you after multiple, multiple samples.
After which, he’d come out, we’d discuss a bit, he’d tell me the results, and then we’d try another tweak. My initial position was scrapped immediately. The first change we made was bringing the bars closer together. That went well, so the next change brought them entirely together. It still wasn’t a problem for me, because my shoulders are narrow and roll over nicely allowing me to keep breathing with a very narrow frontal area.
The arms are closer, the back lower… I’m starting to look like a TT racer.
After that, it was time to move the bars down and keep monitoring how I felt with all of the changes. Every time Mike came out, the numbers got better and better. Every change we made was a significant improvement to the last.
After a certain point, we had seemingly maxed out my low end on the fork – but Mike knows his way around a bike fairly well after wrenching for some awesome teams like the Saturn juggernaut and Rona – he took the top cap of the headset off and voila a little more drop created and an even better position.
The final tweaks were some of the most interesting because at this point the intuitive nature of the process started fading a bit. At one point, we pulled the bars back a little bit toward me in hopes of making me more ball-like, but instead of bringing down my drag coefficient (CdA), there was actually a significant jump, as the shape of my back actually made such a move impossible. An effective position for me is definitely on the more stretched out side of things – of course, whilst remaining within the pesky UCI limits.
That paragraph is obviously specific to me, but that’s the point, everybody is different on a bike, and each person’s basic physical characteristics really impact their position on a time trial bike, and the guys at A2 have the knowledge, experience, and creativity to find what works best for any individual.
How’d I Do?
At the end of the session, we discussed in detail what we had learned. He had been keeping me posted on the data throughout, but once I got a chance to actually sit down and look at it, the changes became very apparent. The changes to my frontal area had reduced my CdA by 15%, which in more real terms resulted in a 10% reduction in my aero-wattage required to pedal at 30mph in the tunnel. This measurement doesn’t account for rolling resistance or drive train friction, but that 10% saved wattage is a pretty good indicator of more speed on the road.
And I still have even more improvement to be made just by adding a TT helmet and a skinsuit.
I was able to look at myself on the computer (always a plus) from three different angles (front, top, side) in every position I tried that day. This filming was then burned to a dvd, and now I’ll have that forever to be able to go back and check on. The raw data was also copied to disc along with the exact measurements of my new position. It’s a fantastic opportunity for me now to go out into the season with this knowledge, and be able to always go back and have this day’s work as a baseline.
The final position of the front end set up reduced my drag by almost 15%.
The Vital Part
The cost. Surprisingly, for something so precise and so pro (I mean, we’re in Lance Armstrong territory here), the costs are reasonable. A2 has officially lowered their pricing to $390 per hour, and the typical session will be in the 2-3 hour range. That’s less than the cost of a good disc wheel – !
They’re open for business and it’s not that hard to get booked in right now – although that could change after a few of you read this article…
• It’s simple and easy to remember: a2wt.com!
Time trials aren’t everything, but to anyone that takes them even mildly seriously, it’s very nice to have this kind of top level tech and expertise available to everyone. This kind of testing was once reserved for top pros only, but now the rest of us can make some real headway into finding that position for going REALLY fast. Of course, it still all comes down to pedaling your bike as hard as possible, but it’s sure nice to reap every bit of reward possible out of what you’ve got.
Book Yourself In!
• Visit www.A2WT.com
for more information or call the office at (704) 799-1001.
THANKS! to the folks at Blue Bikes for providing me with a bike that I could work with and proved more than capable in the wind tunnel. Make sure to have a look at the burgeoning company at BlueBikes.com.