Austin, Texas ? Lance Armstrong’s run of six straight Tour de France victories has raised cycling’s profile in the United States to unprecedented levels.

Professional and amateur organizations say their memberships have risen steadily while millions tuned in to coverage of international racing’s premier event this summer.

Now comes the real challenge. At 32, Armstrong knows he won’t race too much longer, and he might not even ride in the Tour de France next year.

Will the sport continue to grow after Armstrong racks his bike for the final time? Or will it wither like the women’s pro soccer league that couldn’t capitalize on the success of the national team’s 1999 World Cup championship?

“I think it can be maintained,” USA Cycling spokesman Andy Lee said. “Cycling in America has always existed. There’s been a number of world-class events in America. It just hasn’t been in the mainstream.”

Cycling enjoyed a wave of popularity after Greg LeMond became the first American to win the Tour de France in 1986.

The Tour de Trump and its successor Tour DuPont — which Armstrong won twice before being diagnosed with cancer — took the sport around the country before fizzling out by 1997 in a dispute over sponsorship.

Still, there is a thriving American circuit that organizers hope to expand, in part by capitalizing on Armstrong’s success.

The Pro Cycling Tour has a four-month summer schedule with its marquee events in Philadelphia, New York City and San Francisco. All are one-day races. The tour also has three women’s events in the same cities.

Lance Armstrong signs autographs before the start of the second stage of the Tour de Georgia in this file photo from April 21 in Thomaston, Ga. Armstrong won his record sixth straight Tour de France on Sunday.

For the races to be more popular, the sport needs to develop star power in the next generation of American cyclists, said David Chauner, president of Threshold Sports, which owns the Pro Cycling Tour.

That could include Floyd Landis, who races on Armstrong’s team, and Tom Danielson, competing in his first season in Europe with an Italian team.

“We have to do like NASCAR and promote the drivers and let people know who they are,” Chauner said. “Show there’s more personalities and people than Lance Armstrong.”

Lee said it will be hard to capture the magic Armstrong gives the sport. Armstrong’s story as a cancer survivor created appeal beyond the sports pages.

“America lives by its heroes and icons,” Lee said. “Even if you see another American go win a Tour de France, it likely won’t be as special a story as Lance.”

One key U.S. event is the Tour de Georgia, a six-day stage race in April that drew an estimated 748,000 spectators in its second year — undoubtedly buoyed by the fact that Armstrong and the U.S Postal Service team raced and won.

“I hope it’s an indication of what we can do in the future with cycling,” Armstrong said after he won the Georgia race.

Stan Holm, executive director of the Georgia race, boldly predicted attendance as high as 3 million next year.

“A lot of those people are coming out to see Lance Armstrong. He’s a rock star,” Holm said.

But he also identified what he called the “Grateful Dead” pack of hardcore cycling fans itching for a great American race like the tours in Europe, the heartland of the pro sport.

“They are just dying for a major cycling event” in the States, Holm said.

Another race, the United Texas Tour, starts in 2005. It will be an 11-stage, 1,138-mile race starting and ending in the Dallas-Fort Worth metroplex and meandering through western Texas.

Organizers are waiting for international certification and hope to attract as many as 20 domestic and international teams to Armstrong’s native state.

“We’re going after the same riders people watched in the Tour de France,” United Texas Tour spokeswoman Kim Davis said. “We’re hoping to draw a lot of people to race in Lance Armstrong’s back yard.”

Chauner said the tour hopes to run a stage race in California as early as next year and expand its schedule to eight or nine events.

Armstrong may hold the key to it all.

He and his team would boost the profile of any race and add instant credibility for new events.

The title sponsor of the Texas race, the United Supermarkets chain, donated $350,000 to the Lance Armstrong Foundation the day the race was formally announced in February.

The race doesn’t have a commitment from Armstrong to ride, but officials hope he’ll participate in some form. Organizers plan to approach Armstrong’s new team sponsor, Discovery Communications, about potential TV coverage.