As a sporting event, the Tour de France, which begins on Saturday, may well be permanently sullied by the doping scandals of the past few years.

Yet advertiser interest in the bicycling world's most important tournament remains strong, say media buyers.

Ad expenditures have trended up every year since at least 2003. Advertisers in 2007 spent $5.5 million on Tour programming on Versus, up 8 percent from 2006, according to TNS Media Intelligence.

This year the number of sponsors is up from last year, with advertisers like Saab and Anheuser-Busch returning and others like Nestle signing on for the first time, notes Steve Margosian, vice president of marketing solutions at Versus.

“We are on par or have more sponsors than last year. We’re certainly not running behind,” he says. “The key thing for us is that we actually have three or four new sponsors coming in. We feel very good about it.”

All this may come as a surprise considering the reports of doping on the part of top racers. For years, there were whispers of doping, and it finally broke in 2006 when American cyclist Floyd Landis was stripped of his win after failing tests for performance-enhancing drugs. Just yesterday, an appeals court upheld that ruling.

But while the reports have hurt the reputation of cycling among the wider viewing public, the tour still attracts an incredibly desirable audience of affluent, well-educated young men, say media buyers. It's an audience advertisers struggle to find on television.

Moreover, the typical viewer is not just a fan of the tour and its daunting three weeks of harsh riding. He or she is also a rider, and thus an ideal target for endemic advertisers, such as makers of high-end bicycles, which can cost $5,000 or more.

And that core audience has mostly stuck around despite the scandals and despite the retirement three years ago of seven-time champion Lance Armstrong.

An average 171,000 people watched Versus’s coverage of the tour last year. That was flat to 2006 but down by almost half from 2005, when Armstrong won his final Tour de France. An average 315,000 people tuned in that year, according to Nielsen.

“People are attracted to hero athletes so it’s not surprising that ratings went down after Armstrong retired,” says Neal Pilson of Pilson Communications, a sports consultancy. “Look at the impact that Michael Jordan had [on basketball] and the impact Tiger Woods has on golf when he’s not playing.”

Just over 200,000 people were watching earlier this decade, when Armstrong, a cancer survivor, was becoming a household name by winning consecutive races. He lured in curious viewers.

This year sports analysts and media buyers think the audience for the tour will start to climb back up again.

Much of that will come from efforts by Versus and cycling associations to confront the whole doping issue head on. Testing for performance-enhancing drugs has been ramped up, and Versus has adopted “Take Back the Tour” as this year's slogan.

“As long as sports take steps to correct what’s going on, which cycling has done with stronger testing, people won’t abandon the sport because of it,” says David Campanelli, vice president and director of national television at Horizon Media.

As with other sports, what matters is knowledge that the problem is being addressed.

“There’s reason for advertisers and sponsors to be cautiously optimistic because the number of distractions the sport is facing appears to be diminishing,” says David Carter, principal at marketing firm Sports Business Group.

“It appears the organizers are taking a new level of drug testing seriously and sponsors and advertisers know there’s some real commercial appeal in cycling.”