BOISE, Idaho — A Boise company that usually makes industrial knives to slice up Idaho potatoes into millions of McDonald’s french fries added an unusual custom touch to the racing bicycle that Team USA’s Kristin Armstrong rode to an Olympic gold medal in the women’s time trial in Beijing.
Armstrong, who lives in Boise, asked AceCo Precision Manufacturing to use a $250,000 computerized mill to make a so-called “third eye” for her front derailleur, to keep the former world champion from throwing her chain during the race against the clock along China’s Great Wall.
Armstrong finished the 14.6-mile course in 34 minutes, 51.72 seconds Wednesday — 24.29 seconds better than Emma Pooley of Great Britain. Switzerland’s Karin Thuerig was third, almost a minute behind the time set by Armstrong.
Armstrong joins Connie Carpenter-Phinney as the only American women to win Olympic cycling gold; Carpenter won the road race at Los Angeles 24 years ago.
Armstrong’s gear shifting woes are storied, most dramatically in the 2006 world championships in Salzburg, Austria, where she dropped her chain on the second of three climbs but still managed to win by 25 seconds. The 35-year-old American, who was 25th in Sunday’s rain-soaked Olympic road race, now often pauses between pedal strokes to shift, a strategy that keeps her chain where it belongs but can cost precious time.
In a development appropriate for a state with “Famous Potatoes” on its license plates, AceCo’s Eric Jensen and other engineers three weeks ago paused from their regular work that includes making knives for companies including ConAgra Food’s Lamb Weston division and J.R. Simplot Co., the two biggest U.S. french fry makers.
To start, the engineers had a photo of a crudely constructed part that some professional cycling teams use to stabilize their chains during bumpy European races like Paris to Roubaix, France, where riders speed over centuries-old cobblestones at 35 mph.
“We took that idea, and made it really aerodynamic,” Jensen told The Associated Press. The result was a 4-inch-long aluminum part that attaches to the front derailleur on Armstrong’s $20,000 time trial bike.
“To win an Olympic gold medal, you can’t have those delays in your pedal strokes. The whole idea with this device is, she can slam into the gears and she won’t have to think about it.”
The Beijing time trial course climbs for about six miles before a long, high-speed downhill. Armstrong decided to use two unconventionally sized front chain rings to help her climb and descend as quickly as possible.
“Because of the nature of this course, the big ring to the small ring is a big drop,” U.S. Olympic cycling coach Jim Miller said in an e-mail from Beijing.
He called the part “a beautiful piece” — just a few grams, anodized gold for optimistic reasons, with the words “Kristin Armstrong” and AceCo etched with a laser into the aluminum.
AceCo engineers initially used high-pressure water jets to create a plastic model. A crude aluminum version followed a day later. Armstrong tested it on a training ride up the winding, 14.5 mile strip of asphalt that rises 3,500 feet up to the small ski area above Boise.
Jensen, a bicycle racer who knows Armstrong through the local cycling community, says he tried to keep up but gave up after five minutes.
“She waited for all of us at the halfway point,” he said. “She said, ‘The third eye worked great.’ She tried to get the chain to drop, but couldn’t. Her confidence level while shifting really went up.”
The sleek final version has less than a millimeter clearance from Armstrong’s chain and cost “a couple thousand dollars” to produce, Jensen said, including engineering, materials and computer programming time.
Armstrong liked it so much on her time trial bike that she mounted another one to the road racing bike she used in Sunday’s race, where she crashed before losing to Great Britain’s Nicole Cooke by 43 seconds.
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