Gap, France ? L’Alpe d’Huez, the Izoard and Galibier passes. Hard climbs, legendary climbs, climbs that decide the Tour de France.

One bad day, even one bad hour, on those punishing ascents in the Alps next week could end U.S. rider Floyd Landis’ bid for the Tour title. After two weeks of racing and little separating Landis from the other top riders, the Tour is perfectly poised for a thrilling finale.

Landis and the 155 other cyclists who have made it this far, surviving crashes, scorching heat, and 1,664 miles of racing, have all of today to rest their aching muscles, patch up scrapes and sores and focus on the 607 miles that remain to the finish line in Paris next Sunday.

Distance-wise, it may seem that most of the work is done.

Think again.

Tuesday brings the first of three make-or-break days in the Alps. And if those towering mountains don’t sift out a winner, then the Tour could be decided in the last long time trial next Saturday, when the riders race alone against the clock.

“Three big days in the Alps, one big time trial, anything can happen,” said Landis’ Dutch teammate, Koos Moerenhout.

The pack rides through lavender fields near La Batie-Verdun in southern France during the 14th stage of the Tour de France. Sunday's stage went between Montelimar and Gap.

After Sunday’s 14th stage, won by Frenchman Pierrick Fedrigo, Landis was still where he says he wants to be: second overall, 1 minute and 29 seconds behind Oscar Pereiro of Spain.

Landis figured that having the overall lead going into the rest day would have put too much pressure on his Phonak team. So he relinquished it to Pereiro a couple of days before, letting the Illes Balears rival ride ahead and take the lead on Saturday.

Landis is hoping that Illes Balears will try to keep Pereiro in the lead by racing up at the front of the pack – where cyclists expend the most energy – sparing the need for his Phonak teammates to do so. Landis wants to keep his team of support riders as fresh as possible so they can help him up the climbs in the Alps.

“We’d like to have some other teams with some motivation to ride, other than us,” the Pennsylvania native said Sunday.

At some point before Paris, of course, Landis will need to get back the lead if it he is to be the successor to seven-time winner Lance Armstrong. And he is betting that Pereiro, when it really counts, won’t be able to stop him.

Pereiro struggled in the Pyrenees last week and was slower than Landis in the first long time trial at the end of week one. So even if he works miracles and holds off Landis and the rest of the field in the Alps – which even Pereiro thinks is unlikely – Phonak is betting that he’ll succumb eventually in the final time trial.

“He’s not going to give it up easily,” said Levi Leipheimer, a U.S. rider on the Gerolsteiner squad. “But I think Floyd’s right. I think he’s gonna crack.”

Given Pereiro’s flaws, Landis’ bigger worries are the other top contenders like him. Riders like Russian Denis Menchov, Australian Cadel Evans, Spaniard Carlos Sastre or German Andreas Kloeden. For the moment, they are all in Landis’ rearview mirror, trailing him by significant but perhaps not insurmountable amounts of time. In order to win, Landis will need to make sure that it stays that way in the Alps – no easy task.

“In the Alps you can easily lose 20 minutes in one day,” Moerenhout said. If Landis “has one bad day, it’s over.”

The L’Alpe d’Huez climb, 21 switchbacks clinging to a mountain with a ski station on top, comes at the end of a long, hard day of riding Tuesday. Riders will have ascended and descended two other mountains, including the brutal Izoard pass, before they reach the foot of the L’Alpe D’Huez, a legendary spot in cycling that will be crowded with hollering fans, some of whom will have camped there overnight.

“You have to change rhythm completely, right from the start of the climb. That’s the hard part and that is going to hurt, for sure. You have to deal with the pain as soon as possible and not think about it that much and just go,” Moerenhout said of the ascent that the Tour first scaled in 1952. Armstrong was the last winner there, in 2004.

Wednesday brings perhaps the hardest day of riding this year, with the monstrous Galibier pass opening the ball. It goes up, up and up – for 27 miles, peaking at an altitude of 8,681 feet – the roof of the Tour.

Three more climbs follow that, the last an uphill finish. The whole route will take the riders some six hours.

Normally, at this stage, Armstrong often had the race locked up. But he retired last year. Without him and top riders Ivan Basso and Jan Ullrich – sent home on the eve of the Tour because of allegations they were linked to a doping ring in Spain – there is a sense that anything could still happen, even if Landis is the favorite.

“It’s a different race without a big leader,” Moerenhout said. “Everybody thinks, ‘Maybe we can win.”‘

Sunday’s 112-mile stage 14 from Montelimar to Gap, in the foothills of the Alps, was marked by a spectacular crash involving David Canada and Rik Verbrugghe. The scorching sun melted the roads, and they lost control of their bikes on a right-hand turn. German rider Matthias Kessler plowed into Canada and cartwheeled over a safety barrier on the side of the road.