PARIS (AP) — Lance Armstrong believes he can win an eighth Tour de France title, well aware his aging legs are not as strong as they used to be. He is also willing to put such ambitions aside if it means helping teammate Alberto Contador win.

Contador, the 2007 winner, and Armstrong will ride for the Astana team in the three-week race that starts Saturday with a time trial in Monaco. The pairing raises an intriguing question: Can the two Tour de France champions ride together or will their fierce individual agendas divide them?

The 37-year-old Armstrong won the last of his record seven straight Tours in 2005, and his startling comeback has fans worldwide eager to see if he can add to his cycling legend.

“Now it’s 2009, not 2004, 2005 or 2001, that’s different”, Armstrong said in an interview with The Associated Press on Tuesday. “I would love to be eternally young, but I’m not. That’s just the reality.”

“It’s not going to be easy to win,” Armstrong added. “In December and January, I thought it would be easier. It ends up being more difficult than I thought. Perhaps because of the crash, of the complicated season or simply because I’m older now.”

Armstrong said he would be willing to support Contador if it becomes clear the Spaniard is the likelier rider to win the grueling race.

“Out of respect for him, out of respect for the team and out of respect for the rules of cycling, I would do it with pleasure”, Armstrong said by telephone after previewing the 18th stage of the Tour, a time trial in Annecy.

When riders take the start line in Monaco, just one rider — the 40-year-old Spaniard Inigo Cuesta — is likely to be older than Armstrong. The Tour’s oldest champion is Belgium’s Firmin Lambot, who was 36 when he won in 1922.

Armstrong knows the odds are against him, and he would love to prove his doubters wrong.

“They would say that my time has come and gone and that I’m too old, that it’s very complicated, that there are other riders now,” Armstrong said. “I know those things and you could use those for motivation. I know where I am. I’ve studied my performances in training very closely, and I’m excited to race. I’m not sure that I can win, but I can tell you that the person who thinks that I get 10th … he is dead wrong.”

Armstrong overcame testicular cancer to win his first Tour in 1999 and finished a creditable 12th place recently in the Giro d’Italia. Still, most regard Contador as favorite for the world’s biggest multistage race.

Before the Giro, Armstrong broke his collarbone in a crash during the Vuelta of Castilla and Leon in March. Now he has recovered fully.

“The indication I have in training and the tests that I did tell me that my condition is good,” he said. “Maybe not the best of my life, but not too bad.”

As meticulous as ever, Armstrong spent the last four days scoping out the big difficulties he will face during the third and final week of the race – a sure sign his ambition still burns.

However, Contador’s legs are 11 years fresher than Armstrong’s, and Spain’s supreme climber is just as hungry to win.

Armstrong insists there are no conflict of interests on his team.

“We really have a clear-cut favorite (Contador) that we can say he is better than the other contenders,” he said. “Nobody wants to lose. I’m not going to act irresponsibly. Neither will Levi (Leipheimer), neither will (Andreas) Kloeden. And, at the end of the day, we will have to follow the orders of the team’s director.”

Armstrong and Contador, one of only five riders with victories in the three main tours (Spain, Italy and France) don’t know each other well and they have spent little time together.

“The relationship is cordial and respectful – there is not a lot of interaction” Armstrong said. “The language is an issue, a challenge. His English is similar to my Spanish, so the crossover is not easy.”

Astana manager Johan Bruyneel, who oversaw Armstrong’s seven Tour wins, recently said Contador would be team leader.

Armstrong told the AP that Contador would wear the team’s No. 1 jersey on Saturday for the 9.6-mile time trial.

The opening clock race could establish a clear hierarchy within Astana. If Armstrong wins it, it would be hard for the 26-year-old Contador to claim leadership later.

“Of course it’s important, but it’s a long way from Verbiers, the (Mont) Ventoux, (the Col du) Grand Colombier,” Armstrong said, looking toward the brutal third week.

This year, Contador has improved his speed and won the Spanish time trial last week. Armstrong predicts Contador will be fast in Monaco, but tabs Swiss star Fabian Cancellara as Saturday’s winner.

Armstrong also thinks his team will win the Stage 4 team time trial in Montpellier and take the yellow jersey then. It could be on his shoulders that day, or on those of Contador, or draped on his American teammate, Leipheimer.

During his heyday, Armstrong usually destroyed his rivals at the first hilltop finish. The first such finish this year is Sage 7, at Arcalis in the Pyrenees. Armstrong preaches patience this year.

“There are too many difficult parts in the final week,” he said. “Honestly speaking, I plan to be careful in Arcalis. It’s not like before when you had two stages in the Pyrenees and then one week through the middle of France pretty easy and then two stages in the Alps and then one week to Paris.”

According to Armstrong, the major threats to the Astana team will come from Australian rider Cadel Evans, the runner-up in 2007 and 2008, from the Schleck brothers, Andy and Frank, and from defending champion Carlos Sastre of Spain.

Armstrong has said he’s riding again to help fight cancer. He’s also back because of his passion for the sport.

“I’m racing for free because I love it,” said Armstrong, who doesn’t get paid by his team. “I don’t think a lot of people would do it for free. I’m doing it because I want it, because I love it and also because I can. The sport was good to me. I had many years at the top and I’ve made plenty of money. My life is comfortable and I can do whatever I want.”