PERPIGNAN, France — In less than 48 hours, Lance Armstrong will have answered the last unresolved question about his capacity to win an eighth Tour de France: Can he still climb?

The 37-year-old Texan is second overall, but about to face his toughest test in this year's Tour as the grueling three-week race arrives in the Pyrenees mountains.

"That's my question mark, that's your question mark, that's everybody's question mark," Armstrong said. "But we don't have to wait long until we'll find out, that's the good thing."

Armstrong is again eliciting fear among his rivals after an astute move that earned valuable time over his rival and teammate Alberto Contador, plus an impressive show at the team time trial.

He couldn't be in a better position before heading into the mountains. But a lurch Friday in Arcalis, Andorra — the finish of the first of three Pyrenean stages — would bring him back down to earth.

Armstrong didn't take any risks during Wednesday's fifth stage with the mountains looming. Thomas Voeckler of France won the 122-mile ride along a windy Mediterranean Sea from Le Cap d'Agde to Perpignan after a long breakaway.

Fabian Cancellara of Switzerland retained the overall lead, with Armstrong a fraction of a second behind. Armstrong spent the day in front of the main peloton with his Astana teammates, trying to avoid any trouble on roads opened to strong winds.

Usually, Armstrong would dominate rivals on the race's first hilltop finish, but this time he is preaching caution, knowing Friday's stage will be crucial. At the top of the 7,350 foot summit, the seven-time champion will have to answer any doubts about his ability to scale punishing ascents.

"I think I'll be good," he said.

With defending champion Carlos Sastre 2:44 back, two-time runner-up Cadel Evans lagging 2:59 behind and Denis Menchov 3:52 back, the Tour could come down to Armstrong and Contador. The Spaniard is third overall, 19 seconds behind Armstrong. Former Tour runner-up Andreas Kloeden is fourth, 23 seconds back, and Levi Leipheimer of the United States is fifth, 31 seconds behind.

Contador, the 2007 Tour winner, will ride with the support of home fans in the coming days. The stage Thursday is a 112-mile trek in Spain between Gerona and Barcelona, scheduled a day before the big rendezvous in Arcalis.

To Contador's advantage, he's the best climber in the world and his legs are 11 years younger than Armstrong's. He's rejoicing that the race is finally reaching his usual playground.

"I can't wait to get to the mountains because it's my territory. The sensations are good, but I always like to confirm them," he said.