Lance Armstrong has no doubts about the risks that lurk in the next stage of the Tour de France: If luck goes against him, he says, his drive for a record sixth straight win could be over almost before it has begun.

One of the obstacles for the five-time champion will be bone-shaking cobblestone paths that some riders say shouldn't even be part of cycling's showcase race.

The paths are bumpy, unsettling and treacherous when wet -- in short, a recipe for crashes.

"Everybody is worried," the 32-year-old Texan said on Monday. "It's always dangerous. You have to be in the front. If you get stuck behind a crash or something like that, then you could almost say that your Tour is finished."

Armstrong is fourth overall, 18 seconds behind overall leader Thor Hushovd of Norway. He finished 85th in Monday's 122-mile second stage from Charleroi to Namur in Belgium, with a small detour into neighboring France.

So far, Armstrong seems pleased, saying his team "is maybe the best one we've had." But the competition is perhaps the toughest he's faced.

"The field is full," said Armstrong, who won't look to take the lead until later in the three-week race. "The course is tough, but I think the competition will be deeper than other years."

Armstrong's biggest rival, 1997 Tour winner Jan Ullrich, is a mere 15 seconds back. He finished 38th in the second stage, with the same time as Armstrong. He looks lean and hungry -- a fact Armstrong played down.

"He always looks good at the Tour," Armstrong said. "The way somebody looks doesn't really mean much."

The two cobblestone sections on Tuesday will come in the second half of the mostly flat 130-mile stage from Waterloo to the northern French town of Wasquehal.

They are fueling worries after two nervous days of crashes and high-speed sprints. The relatively flat early stages provide a chance for glory for sprinters who have no real hope of winning the Tour when it ends in Paris on July 25.

The speedsters include Australia's Robbie McEwen, who dashed to victory in a mass sprint at the end of Monday's stage.

In finishes like that, Armstrong and the other riders who wait until the mountain stages to make their move just do their best to avoid spills.

Armstrong summed up the early stages succinctly, "Very fast, very nervous, dangerous finishes."

"It's really stressful. In the last 20 to 30 kilometers [15 to 20 miles] the pace really picks up and everybody fights," said American Levi Leipheimer, who is 13th overall. "All etiquette is out the door. You do what you can -- you scratch and bite and do whatever."

The first cobblestone section Tuesday will run for 1.7 miles. The second, 15 miles from the finish, is nearly three-quarters of a mile long and also forms part of the Paris-Roubaix race, a grueling classic known as "the Hell of the North."

Flat tires, crashes, crowds are all potential hazards.

"Some people's Tour will be finished," Armstrong said. "I could be one of those people, and I'm not dumb enough to think that I couldn't be. And that would be a shame."

For this Tour de France fan, watching the end of yesterday's stage proved to be an uplifting experience.