BIKE RACING, AT ITS ESSENCE, is about pain. According to the hackneyed but ultimately reliable theorem, great bike racers draw their strength from fights they've encountered elsewhere in life—against poverty, abusive or absent parents, injury, or illness (or, with surprising frequency, all of the above). But even in a peloton brimming with poor tough kids from the wrong side of the tracks, Landis manages to stand out.

"Floyd once told me that during races, it made him feel better to know that there probably weren't too many other guys who'd shoveled out a septic tank in tattered shoes in the winter," Z-Man told me. "So he's got that going for him."

The essentials of the Landis biography tread perilously close to myth: He was born in Farmersville, Pennsylvania, the second-oldest of six children in an observant Mennonite family. Rules were simple: no television, movies, uncovered heads for women, dancing, or anything that brought glory to the self instead of God. When Landis discovered mountain biking (which was permitted, so long as he covered his bare legs with cotton sweats) at 15, he improved so fast that, when he told his parents he wanted to pursue it as a career, they warned him of God's wrath. When he wouldn't listen to Scripture's logic, his father, Paul, tried a different tack. He saddled Floyd with an endless list of strenuous chores: fixing the car, painting the barn, digging the septic tank. If the boy was too tired, the logic went, he couldn't ride—a theory that Landis quickly disproved by training at night, often returning to the house at 2 or 3 a.m.

"My parents are good people; we get along fine now," Landis says. "But that life wasn't for me. I was determined to get out, and I knew my bike was the only way."

Landis won the junior national mountain-biking championship at 17, in 1993, and moved to California two years later. When a curious coach measured his VO2 max (generally thought to be a decent indicator of endurance potential), Landis scored nearly 90 milliliters per kilogram per minute, almost two points better than five-time Tour winner Miguel Indurain.

Before arriving in California, Landis's American cultural experience had consisted mostly of a single viewing of Jaws when he was 12. ("I had to call my mom to take me home," he says.) While his friends likened him to an unfrozen caveman, Landis set about exploring culture with the resolve of a scientist. Mountain Dew and Kid Rock were judged worthwhile; disco and Oliver Stone movies, not so much.

"His mind is very uncluttered," says Will Geoghegan, 35, his former teammate on the Team Chevy Trucks mountain-bike squad. "He's able to see and understand things more clearly than the rest of us."

Landis saw that pro mountain biking was fading and decided, in 1999, to switch over to domestic road racing. He was spotted and signed by U.S. Postal in 2002 and quickly became friends with Armstrong, who appreciated Landis's offbeat humor and, even more, his toughness. The latter quality shone most vividly in 2003, when Landis broke a hip in January, had surgery in April, and still managed to ride powerfully in support of Armstrong in the Tour.

Those good feelings came to an end in 2004, when Landis decided not to join U.S. Postal's new incarnation as the Discovery Channel team. The decision precipitated a feud: What Floyd saw as independence, Armstrong saw as disloyalty. Over most of 2005, the former friends traded words, sharp elbows, and the occasional not-so-subtle gesture (Armstrong pointing derisively to the clock after beating Landis on a summit finish at last April's Tour de Georgia; Landis yelling "Discover this!" after beating Armstrong in a time trial). At June's Dauphiné Libéré, Discovery Channel adopted defensive marking tactics designed to prevent Landis from winning, even at the possible expense of the team's own results. By week three of the Tour de France, Landis and Armstrong were shouting at each other from the bike. It was not a particularly smart fight for Landis to keep up; few people have tangled with Armstrong and come out the better for it. But it's a measure of his stubbornness that he refused to back down.

"That's Floyd all over," Jonathan Vaughters says. "He's exactly like Lance in that way—they've both got an angry core, a chip on their shoulder. And as Floyd matures, he's getting more successful at channeling that anger in a positive way."

When the 2005 season ended and Armstrong retired, the dispute quickly cooled. Both sides went out of their way to extend olive branches, a process that accelerated when Discovery team director Johan Bruyneel, with Armstrong's blessing, took Landis out to dinner and tried to recruit him to join their team. ("Johan even paid!" Landis recalls with a smile.) While Armstrong and Landis are not as close as they once were, things are civil, even warm. When Landis won Paris–Nice, Armstrong e-mailed his congratulations.

"A year of that was too much," Landis says. "I'll take whatever responsibility is mine for what happened. In the race, it can be like a video game—you're killing this guy or that guy. But then afterward you turn it off and everybody's real people again.

"I saw firsthand what Lance did, and it was superhuman," he continues. "I saw how his system worked. It's not necessary for me to be like Lance in every way. But there are some things that I want to take from that and use."

For instance?

"His boldness at taking charge of things. His willingness to say, This is what I want, and I'm going to take it. It's very hard to compete against that."