I'D HOPED TO INTERVIEW Thomas Weisel during a bike ride, since there's not much else to do besides talk. "I wouldn't recommend that," warned Steve Johnson, athletics director for USA Cycling. "When he rides, he puts his head down and goes." Weisel's friends say that's his approach to life in general. "God help you if you stand in his way," one told me. "The road is littered with carcasses."

In the end I'll be spared anyway—"I'm 20 pounds overweight and buried in business," Weisel said over the phone. We'll meet for lunch in early March at San Pietro, a swank Italian restaurant in Midtown Manhattan. Standing almost six feet, the barrel-chested Weisel still looks like the track athlete he used to be. His silver hair sweeps back from his forehead as though it's permanently windblown from all the high-velocity sports he's done in his life: speed skating, alpine skiing, sprinting, and racing bikes.

"I'm chemically dependent on exercise," he tells me as we sit down. "It doesn't really matter what sport it is, but cycling has been my great savior. It keeps me competitive and active.

"But in this country it's under the radar, underappreciated, and underfunded," Weisel adds. "Lance has set off a grassroots movement that is sustainable. But we've got to get more races in the U.S.—and the Champions Club is the absolute crux. We're just getting started."

The next morning, Weisel will fly out of New York in time to have lunch in San Francisco, then go on to dinner in Sun Valley, Idaho, where his two youngest children, ages seven and 11, compete on the local ski team. Weisel lives in Marin County, California, with his kids and his third wife, Emily Carroll, 40; the family flies his private jet up to Sun Valley on weekends. "It's one of the few luxuries I've afforded myself," he says. Another is a beach home in Maui, where he surfs with his kids and occasionally paddles out with Lance, who, Weisel confides, "is an amazing surfer."

Weisel grew up speed-skating in Milwaukee, which helps explain his competitive drive. In the fall of 1959, when he was a Stanford freshman, he had one goal: to win speed-skating gold at the 1960 Winter Olympics in Squaw Valley. He'd placed third at the Olympic Trials in 1959. Then he spent that fall living the fun-filled life of a freshman instead of training, and he ultimately lost his spot on the team.

"I was ready for the next phase of my life," he says, shrugging off the disappointment. But Weisel's actions tell another story. He returned to California after graduating from Harvard Business School in 1966, and channeled his ambition into business. By 1982, at age 40, he was CEO of his own investment bank, Montgomery Securities. "The competitive fires were still burning," he says, and he had plenty of excess energy to channel into sports.

Weisel started ski-racing at 35, hiring the best racing instructor in Sun Valley. In 1982, he placed third in the Masters National Championships; the next year he became president of the U.S. Ski Team. When bad knees forced him to switch to cycling three years after that, he once again hired the best help he could find—Eddie Borysewicz, the Polish-born coach of the U.S. Olympic cycling team, which had won nine medals in Los Angeles in 1984.

With advice from the legendary Eddie B., Weisel began training seriously to win a world championship in his age group. Twice a week, he flew down to San Diego to train on the velodrome with the U.S. national track-cycling team. Their brutal interval workouts started at 10 a.m. and lasted until 5 p.m. On "off" days, Weisel sometimes worked out two or three times, rising before six to ride or lift weights and finishing late at night.

Weisel was accustomed to pain. In his 2003 autobiography Capital Instincts, he writes that his father—a Harvard-trained surgeon—"kept a stick handy for the purpose of beating the shit" out of him and his brother, Richard. Next to that, the rigors of training were almost cathartic. Between 1989 and 1991, Weisel won three masters world championships and five national titles on the road and track.

When it was all over, a friend asked if it had been worth it. His reply: Yeah, but only because I won.