LES ROUSSES, France — Lance Armstrong is predicting a shakeout among the top Tour de France contenders with the race heading to the Alps for its first serious climbing.
    The seven-time Tour champion and his main rivals struggled under hot and muggy conditions Saturday when French rider Sylvain Chavanel won a seventh stage that included six low- and midlevel climbs in the eastern Jura mountains.
    It was a foretaste of the climbs to come: the pack embarks on serious Alpine punishment Sunday with a 117.4-mile jaunt that features two very difficult climbs in the run between the Les Rousses and Morzine-Avoriaz ski stations.
    If the Texan wants an eighth Tour crown, he'll need to excel in the mountains. The stages in the Alps on Sunday and Tuesday are important, but four leg-straining days in the Pyrenees in the third week may be decisive.
    While he "suffered" Saturday, "there will be selection tomorrow, it won't be like today," Armstrong said. Overall, he trails 2009 Tour champion Alberto Contador by 50 seconds and world champion and two-time runner-up Cadel Evans by 1 minute, 51 seconds.
    Despite Sunday's uphill finish into Morzine-Avoriaz, Armstrong believes the day's first big climb — the 8.9-mile Ramaz pass — will be the key. It has patches where the gradient rises to nearly 10 percent.
    "It's super hard if we have temperatures like this, people will just be stuck on the road," he said.
    The forecast was for temperatures up to 91 degrees in the plains, and the 38-year-old Texan, who is competing in his 13th Tour, noted that roads can melt under the heat and cause havoc for riders.
    "If you hit it just right (your tire) will slip for a while and then it will grab, and you'll just high-side (topple off) immediately," he said.
    On Saturday, Armstrong and other leading contenders finished 1:47 behind Chavanel, the Quick Step rider who won his second Tour stage this year in the 101-mile trek from Tournus to Station des Rousses.