Cutting Edge 2008.12.pdf

CUTTING EDGE

Wind Tunnel Vision

Athletes ine-tune their cycling aerodynamics for

maximum eficiency and speed.

By Jim Rutberg

the A2 Wind Tunnel—a second, smaller facility to meet the growing

demand from lower-budget motorsports teams as well as amateur and

professional cyclists and triathletes. In this case, sponsors including

Proile, Guru, SRAM and Retul footed the bill.

Mike Giraud is the cycling specialist at the A2 Wind Tunnel, and

with more than 20 years of experience in the cycling industry and

a professional, patient and no-nonsense approach to aerodynamic

testing, he makes sure athletes get maximum value from their time in

the tunnel. At a fraction of the cost of time in the big tunnel, anyone

can walk out with an optimized aerodynamic position that will save

more time than a new set of wheels.

“I’ve spent a lot of time in wind tunnels, and not only does Mike

know his stuff, he’s also a great guy to work with,” Golich said. “I was

amazed at how many trials we completed in just a few hours.”

Truth be told, Alexander and Ficker probably would be willing

to pay just about any price for a greater chance of victory at the Ford

Ironman World Championship. Last year Alexander inished only

3:30 behind winner Chris McCormack.

What difference could aerodynamics make? Well, all other things

being equal last October, going just two seconds per mile faster on the

112-mile bike leg would have cut 3:44 off Alexander’s time and enabled

him to break the tape. Ficker was a bit farther off the winning pace

set by Michellie Jones in 2006, but as a run specialist she had more

room to improve on the bike starting with her aerodynamics.

There are two ways to go faster on a bicycle: put out more power or

slide through the air more smoothly. In their quests for Ironman glory,

professional triathletes Craig Alexander and Desiree Ficker aim to do

both. This past July it was the pursuit of free speed that drew them,

supported by their sponsors and coaches, to the AeroDyn Wind Tunnel

in Mooresville, N.C., deep in the heart of NASCAR country.

Carmichael Training Systems headquartered in Colorado Springs,

Colo., whose coaches Nick White and Lindsay Hyman work with

Craig Alexander and Desiree Ficker, respectively, spearheaded the

trip. Company founder Chris Carmichael and CTS Premier Coach

Dean Golich were members of the “F1 Group” of experts assembled

to help seven-time Tour de France champion Lance Armstrong

optimize his cycling position, equipment and training. They believed

a similar effort, with input from Alexander and Ficker’s equipment

sponsors, could dramatically improve the athletes’ performances

at the 2008 Ford Ironman World Championships in Kona, Hawaii.

Both athletes have inished second in Kona—Alexander last year

in his debut race in Hawaii, and Ficker in 2006—and entered the

2008 season eager to take the necessary steps to win triathlon’s most

prestigious event.

Mooresville is a small town just north of Charlotte and is home

to more than 60 motorsports race teams, which test their cars and

trucks at the AeroDyn Wind Tunnel 24 hours a day, ive days a week,

at a cost of nearly $1,500 an hour. The AeroDyn owners also built

CyCling AerodynAmiCs 101

The ultimate goals of visiting a wind tunnel are to reduce the

total aerodynamic drag generated by the combination rider and

machine, and to simultaneously put the athlete in a powerful riding

position that he or she can maintain for the duration of the ride. The

rider is the biggest problem, being responsible for about 80 percent

to 85 percent of the total drag. To bring that drag number down,

TRIATHLETEMAG.COM | DECEMBER 2008 | TRIATHLETE 145

CUTTING EDGE

First up: CrAig AlexAnder

Prior to visiting A2, Craig Alexander had never stepped into a

wind tunnel. As with most athletes, his cycling position had been

honed by a combination of trial-and-error and a series of bike its,

so the irst step was to test his current position and establish baseline

drag numbers. Giraud set up Alexander’s Orbea Ordu in the tunnel,

cranked up the wind with just the bike, and then again with Alexander

sitting perfectly still on the bike.

“The irst thing we noticed was that Craig’s frontal area and CDa

[drag coeficient times area] were already remarkably low,” White

said. “Typically, elite cyclists can achieve more aerodynamic positions

than Ironman triathletes because their time trials are one quarter to

one third the distance of an Ironman bike leg. Craig’s initial numbers

were a little high for an elite cyclist, but very low compared to most

long-distance triathletes.”

“ Winning in Kona still comes down to

being the strongest athlete on that day,

but it’s valuable to do the testing and

know your equipment and position are

helping you go faster.

”

—Craig Alexander

Since Alexander’s cycling position and sustainable power output

were already quite good, White and Golich decided to focus their

attention on optimizing the athlete’s equipment choices and riding

strategies. “The wind tunnel doesn’t only show an athlete’s laws; it

can be very important for conirming that their current position is

good, which then helps them avoid unnecessary—and potentially

detrimental—changes,” Golich said.

By the end of the session, Craig Alexander had been in the wind

tunnel for 27 individual runs over about three hours, these runs

measuring the impact of changing everything from the position of

his head and ingers to the height of his stem and his choice of water

bottles, and a new set of aerobar extensions from Proile. While his

coach, Nick White, wouldn’t reveal Alexander’s actual drag numbers,

he indicated that the top three aerodynamic savings came from:

• Ducking his head: By lowering his head to ill the space between

his upper arms, Alexander dramatically smoothed the airlow

around his body. This was so effective that it even negated the

normally detrimental impact of looking down, which causes the

tail of an aero helmet to stick up into the air and generate more

drag.

• Raising his behind-the-saddle water bottle: In terms of aerody-

namics, carrying luids is a necessary evil for Ironman triathletes,

and with Alexander’s body proile, behind the saddle is actually

one of the worst positions for a bottle. To minimize the drag

caused by this bottle, White raised it as much as possible so it

sat in the already-turbulent air behind Alexander’s back instead

of blocking airlow around the slender seat post of his Orbea.

• Responding to speed and wind: Perhaps the greatest beneit of

wind tunnel testing is increasing the athlete’s awareness of their

position. By cranking up the wind speed in the tunnel, White and

Golich were able to show Alexander the true beneits of holding

his hands and head in the optimal positions when going fastest

or riding into a hard headwind.

you have to reduce an athlete’s frontal area—the total surface area

facing the wind—and help the air low more smoothly around the

athlete and bike. But the best possible position from an aerodynamic

standpoint may be the worst in terms of comfort or power production,

so that an athlete’s optimal position is the result of a long series of

compromises.

“Cutting 100 grams of drag saves an athlete about 15 watts at 30

mph,” Golich said. “Bike speeds at Kona average closer to 24 to 25

mph for the men and 20 to 22 mph for the women, but cutting drag

will allow Craig and Desiree to go faster with the same power outputs,

or go the same speed with lower workloads.” Either scenario would

be beneicial, the irst resulting in a faster bike split and the second

leaving the athlete with more energy for a faster marathon.

146 TRIATHLETE | DECEMBER 2008 | TRIATHLETEMAG.COM

CUTTING EDGE

“ … I’m conident that in the end I’ll go

“It was a great experience,” Alexander said. “I’m glad there were

no major changes needed in my aero position, but I came away with

very effective ways to go even faster on the bike. Winning in Kona

still comes down to being the strongest athlete on that day, but it’s

valuable to do the testing and know your equipment and position

are helping you go faster.”

faster on the bike and maybe even have

more energy left for the run.

”

—Desiree Ficker

next up: desiree FiCker

In contrast to Alexander, Ficker is having her position on her

custom Guru Crono undergo signiicant changes. “When Desiree

was more focused on being a runner, her cycling position gravitated

toward a more neutral triathlon setup,” said her CTS coach Lindsay

Hyman. “Now we want to gradually move her to a more aggressive

cycling position so she can generate more power.”

In terms of priority, comfort and power gain importance relative

to aerodynamics as events get longer. Based on a Retul bike it in May

using infrared motion-capture technology, Hyman has a long-term

plan to move Ficker into a more powerful position on her bike, but

it may take until the 2009 season to get there. “A primary goal of the

visit to the wind tunnel was to allow Desiree to see the beneits waiting

for her at the end of this process,” said Hyman. “We knew—even

before the wind tunnel—that these changes would make her more

powerful, but it helps to see that she’ll be able to generate more power

and have less drag at the same time. It makes the uncomfortable work

of changing her cycling position worth the effort.”

“The position we’re working toward is deinitely aggressive,”

said Ficker. “Right now I wouldn’t be able to ride 112 miles like

that and then produce a great run, but we’re changing the position

in small steps over a long period of time and I’m conident that in

the end I’ll go faster on the bike and maybe even have more energy

left for the run.”

As with Alexander, the team of coaches and experts also focused

on individual equipment and behavior changes that could save Ficker

time and energy. Currently without a helmet sponsor, she was free to

experiment with various lids. One design with a long tail was fastest

for her when it was perfectly positioned over her back, but that same

tail section cost her a lot of speed when she looked down. Over the

course of a ive-hour Ironman bike leg, the team felt the losses would

outweigh the gains, so they went with a more conservative design

that generated a little more drag in the perfect position, but was far

less detrimental when Ficker moved her head.

“Regardless of the helmet, one of the big things we noticed with

Desiree is that when she’s tired her head moves forward and down,

but not into an advantageous position that ills the gap between her

arms,” said Golich. “As she continues to train and compete, it will be

important for her to focus on keeping her head more in line with

and closer to her body, especially as she fatigues.”

Hyman is also quick to point out that Ficker started out with

some natural advantages on the bike. “She has a great body proile for

cycling aerodynamics,” he explained. “She has a very slender upper

body and also narrow hips, and that combination works really well

for total frontal surface area and airlow. We want to take advantage

of that and increase her power output, all from a position that she

can maintain for a full 112 miles.”

“Overall I’d say it was a very successful day,” said Golich, the team

member with the most experience in wind tunnels. “Nick and Craig

made some adjustments that could take three to ive minutes off his

bike leg in Kona—and that’s without any increase in power output.

If he’s stronger and makes the adjustments, he could potentially go

even faster. And I think Desiree and Lindsay are headed in the right

direction with her position on the bike, and it’s important that they’re

moving gradually. Major changes all at once almost always do more

harm than good.”

148 TRIATHLETE | DECEMBER 2008 | TRIATHLETEMAG.COM

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