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By Lennard Zinn
Losing a minute and a half to Jan Ullrich over the 47km between Gaillac and Cap’Decouverte in the Tour’s first long time trial was probably not what Lance Armstrong had in mind when he worked with Nike to develop the Swift Spin skinsuit that he, his teammates and the category leaders wear in the Tour time trials.
The suit should “give about 30 seconds to a minute advantage in a 58km Tour de France individual time trial depending upon what version of the suit is worn,” according to Dr. Chester Kyle, the cycling aerodynamicist heading up the Swift skinsuit project.
Armstrong also did not plan on having TV cameras focusing on the back of his left thigh during the effort, showing the tear that was developing in the suit and probably throwing off its vaunted aerodynamics. And he most certainly did not expect to get so dehydrated during his time trial effort that he would lose four kilograms off of his already gaunt body and end up on IV liquids overnight, either!
Whether the tear and the dehydration had to do with the suit’s design or solely with mistakes that Armstrong and his team made are questions that may not ever be answered. However, we do know that the suit has some very interesting technology in it. The basis for the Swift Spin is found in the Olympics in the suits in which Australian Cathy Freeman won the 400-meter gold and American Marion Jones won five medals in track and field in Sydney in 2000, as well as in those worn by the U.S. and Dutch speedskaters to win 20 medals and set eight world records in 2002 in Salt Lake City.
To adapt the technology for cycling, Nike organized a team at the University of Washington wind tunnel called Project Swift a division of Nike’s Advanced Innovation Team (AIT).
The team was made up of Rick MacDonald and Matt Nordstrom of Nike and Canadian aerodynamicist Len Brownlie as well as Kyle, famous for having developing the aero’ bikes, helmets and suits for U.S. team riders for the 1984, 1992 and 1996 Olympics. The team originally also contained Armstrong’s aerodynamics adviser, John Cobb, who later chose to leave the project.
This kind of focus on a cycling suit is unprecedented and produced a unique result.
According to Kyle, “Like the speed skating skins worn by the USA and Holland in the long track speed skating events, the USPS Swift Spin suits have several design features to lower aerodynamic drag. They use ‘zoned’ fabrics to minimize drag on the arms, thighs and torso. They have directional seams that follow the flow lines (no cross flow seams), and they are carefully fit and the materials are selected to avoid wrinkles when the rider is in racing position. The result is about a 5-percent drop in overall wind resistance compared to the suit it replaces.”
The team tested dozens of fabrics and multiple versions of the suit, and an alpha version of it was tested during the 2002 Tour de France. It has evolved to become even lighter and more breathable for 2003. Nike has patented the “Zoned Aerodynamics Technology,” a process that strategically places fabrics over various body parts in relation to the speed at which they move. This combination of lighter materials, a calculated change in the placement of some mesh panels and vents, and the introduction of Nike “No-Sew” and non-stitch apparel fabrications are the advancements from 2002, resulting in yet less air drag and better heat regulation.
It’s a good thing, too, because Armstrong had enough trouble with heat regulation in stage 12 as it was, and he needed every bit of aerodynamic advantage he could get to stay close to Ullrich.
“We took everything that we learned from the Sydney Swift Suit and the Salt Lake Swift Skin and applied it to cycling,” says project director MacDonald, “Our team looked at cycling in a way that no one ever had and combined it with the technology we already had in-hand from track and field and speed skating. With cycling, the body is in different positions, the speeds are different; different parts of the body are moving at different speeds. Countless hours of wind tunnel testing by Nike show a significant benefit to wearing the Swift Spin over any other suit we tested and we tested a lot of other suits.”
At its onset, Project Swift investigated more than 50 textiles and tested them for several key qualities including wind resistance, elasticity, and breathability. Using an advanced form of “body mapping” known as Nike Zoned Aerodynamic Technology (another patent, of course), the team placed six selected fabrics on certain body locations to work strategically and harmoniously with the athlete’s unique motion in relation to airflow.
The effect of the differently textured fabrics on the body is similar to the one that dimples have on a golf ball during flight.
From a distance, the suit resembles a conventional cycling time-trial suit, coming in both short- and long-sleeved versions, although the legs are a bit longer than conventional suits, due to the leg “trip cylinders” of textured fabric to reduce drag.
“That (leg) extension is longer and made of a different fabric than other parts of the suit for specific aerodynamic reasons,” says senior designer Nordstrom.
Also critical to the Swift Spin are the direction and placement of seams in the suit. When possible, Swift Spin seams are aligned with the airflow direction or placed completely out of its way to further reduce drag. Where appropriate, the Swift Skin is articulated to minimize creasing, which could “trap” air and slow the rider, and the fit of suit is very tight. “We changed the fit to be more streamlined and close to the body when the rider is in the time-trial, aerodynamic position,” says MacDonald. “This suit is tight. Any kind of streamlining that you do on a suit like this reduces drag. It not a comfortable suit for walking around, but when you’re in that special aerodynamic position, it fits like a glove.”
No-stitch elastic leg grippers and wrist elastic cap the whole thing off. The suit may be incredibly aerodynamic, but heat is of great concern for cyclists, both of the body and environment, and this has been particularly apparent in this hot Tour de France.
“The conditions are relatively cooler in speedskating,” says MacDonald. “And track sprinters are in their suits for relatively little time when compared to a cyclist. We used lighter-weight fabrics on the Swift Spin in most places, although the suits do share a lot of similar textiles. We had to rearrange those fabrics in a new pattern due to thermoregulation demands on the bike.”
Ventilation in the front would be poor aerodynamically, so mesh vent panels have been located in back behind the air flow. Whether the suit was sufficiently thermoregulating, given Armstrong’s dehydrated condition at the end of the time trial is an open question.
We asked Nike about the problems encountered in the Stage 12 time trial and the company’s Scott MacEachern said the “short answer is no, the Swift Spin had nothing to do with it.”
MacEachern rushed to see Armstrong at the Postal bus moments after the TT. He said he got no indication from Armstrong that he thought the suit was giving him thermoregulation problems.
Nike officials said their own research indicated that the suit “was not only more breathable (technically “Resistance to Evaporative Transport” Test or RET) and cooler (“Resistance to Conductive Transport” Test or RCT) than all competitors’ skin suits that we tested, but it was actually cooler and more breathable than a cotton t-shirt.”
Well, breathable or not… Saturday’s stage is going to be about 25 to 30 degrees cooler than it was in Cap’Decouverte. With a storm blowing in from the Atlantic, rain and probable tailwinds, dehydration probably won’t be at issue…now maybe if they stitched in a sail!