Written by Calvin on February 10, 2011/Park Tool News
Wind Tunnel Time for the Kelly Benefit Strategies—OptumHealth Pro Cycling
Submitted by ERIC JELLUM – HEAD MECHANIC, KELLY BENEFIT STRATEGIES—OPTUMHEALTH PRO CYCLING
It’s that time of year when Pro teams are sending the TT specialist to the wind tunnel to tweak their positions. Nowadays though, not only do the fast time trialists visit the wind tunnel but also GC riders will spend time working on their technique. The time spent in the wind tunnel is very valuable and even the smallest changes can pay off big with wins later on in the season. Not, only does the wind tunnel help the riders become more aero it’s also a great showcase for the teams sponsors to feature the newest equipment.
This year the Kelly Benefit team is bringing 4 riders to the A2 wind tunnel in Mooresville, NC. We will be at the tunnel for a single day, so depending on how much tweaking a rider needs they will get about 2 to 3 hours each in the wind tunnel. I have visited the wind tunnel about a half a dozen times before and every visit I learn something about aerodynamics in relation to bicycles and riders. In years past I have gone to the wind tunnel with upwards of 9 riders and shuttled them through over the span of 2 full days.
Here is a little tidbit of information. Air is actually being sucked through the wind tunnel and is not blown directly at the rider. The air is being sucked by large fans that are located at the back of the tunnel and the front of the tunnel is lined with a thick honey comb material that directs the air with very little turbulence.
We are very fortuniate to have some great people helping the team out once we are at the wind tunnel. To ensure we are taking advantage of everything the wind tunnel has to offer we bring in an aerodynamic specialist. Chris “Dino” Eden will be accompanying us to Mooresville, NC. Dino works at HED (the teams h/bar and stem sponsor) and he has a vast knowledge of aerodynamics and knows what it takes to make a bike and rider faster. Along with Dino, we have Mike Giruad who runs the A2 wind tunnel. Mike is a former mechanic for Team Saturn, he knows bikes and also how to decipher all the numbers coming off the multiple computer screens from sensors that are located in the tunnel. With these 2 guys running the show a lot of work can be accomplished in a short amount of time.
Mike and Dino will put a rider in the tunnel right away with their current position just to get some drag numbers to see where and how they can improve. For a rider to be tested in a single TT position it will take about 15 minutes. In that time the Mike will fire up the fans, record a baseline number, then the rider will be instruct to start pedaling for a few minutes, drag numbers will be recorded and then the fans will be powered down. The numbers will be compared to the previous run and changes will be made to the riders position based off the numbers recorded. Mike and Dino will go back into the tunnel and talk with the rider to see how they felt in the new position and changes will be made accordingly. Then the whole process is repeated multiple times till the rider is not only aero but also can breathe and pedal comfortably in the new setup. 95% of the changes to the bike will be done on the front end. Stack height, bar extension and arm rest pads can all be changed to increase the rider aerodynamic advantage. Not only will changes be made to the bike, but suggestions will be made to the rider on how they should position their neck and shoulders to be even faster.
You may be asking yourself “Eric, why would you need to go to the wind tunnel when the team has enough support to take care of the riders?” Well, I can tell you that I don’t go to the wind tunnel to really help out with anything inside the “breeze tube.” All my work is done even out the master control room.
With only 4 riders visiting the wind tunnel, I had all the bikes and equipment needed shipped to the hotel to arrive the day before our session. This enables me to build all the bikes up that night to get everything ready. Because, once the clock starts at 8 a.m. their are no time outs to get organized till the end of the day at 5 p.m. Even though to rent out the A2 wind tunnel for a single day or even a single rider is not as expensive as it may seems, the total expense on the team for all the plane tickets, hotels and rental cars can add up quickly. So it’s very important that everything runs smoothly. Along with being organized I also to make sure I have a good stock of extra stems, base bars and different bend extensions on hand to make changes to the riders position. Again, there are no time outs at A2 to go out and find a bike shop for extra components.
When I prep a bike for the wind tunnel, I remove all the cables and housing. This makes it much easier on the engineers to make any changes to the riders position once in the tunnel. It is much quicker to swap a stem or change the stack height on a bike without a bunch of cables and housing in the way. I’ll set the front derailleur limit screws so the chain stays in the big ring and I will cut down a brake cable to a few inches then insert it backwards through the rear derailleur to imitate enough cable tension to engage the bike in the 17t cog.
Before a rider gets tested, I copy down some basic bike measurements just so I can compare the bike to the new measurements once the testing is complete. Once we get that first rider going, I’m already focusing on the next bike that will be put through the tunnel. So when that first rider finishes his time, I will immediately take the bike and copy down all the new measurements in great detail. The spreadsheets I carry for the riders who visit the wind tunnel have pretty much every measurement that can be pulled off a bike. Believe it or not, just about every time I get a bike back from Mike and Dino they have raised the riders handlebars up a few centimeters. So the old theory that lower is faster, is not always true. That’s the great thing about wind tunnel testing, the numbers being recorded don’t lie. A riders TT position or current bike setup may look fast, but until it’s put into the wind tunnel no one really knows. Once new bike measurements are taken, the bike gets packed back up in the box and gets a shipping label slapped on it. This whole process it completed till all the bikes are sitting by the door waiting to be picked up by Fed-Ex.
All the riders and the staff will usually be flying out of Charlotte, NC which is about 30 miles from Mooresville. So it’s a race to the airport to catch that evens last flights of the day to make it home. This year our visit to North Carolina for the A2 wind tunnel will take exactly 24 hours from touch down to take off. With the regular season of racing requiring so much travel, we try to keep any extra time away from home to a minimum.
With the domestic race calender becoming more demanding on all-rounders, the early season time spent at the wind tunnel is crucial. It won’t take long for us to find out if our time in Mooresville will pay off, because the season is right around the corner.
The race is on!