Hamilton bows out of Tour

PLATEAU DE BEILLE, France -- Tyler Hamilton pulled out of the Tour de France because of an ailing back yesterday, eliminating one of the top threats to Lance Armstrong's bid for a record sixth straight title in cycling's premier race.

Hamilton, of Marblehead, Mass., climbed into a vehicle used by his racing team, Phonak, shortly before the halfway mark in the 13th stage, a 127.7-mile course from Lannemezan to Plateau de Beille.

His severe back pain was less noticeable in the early, flat stages than in the Pyrenees, which the race entered Friday.

"He has bruising all down the left of his back," Phonak manager Urs Freuler said. "When you are in a climb you need the output from the back muscles." In the sixth stage July 9, Hamilton fell hard in a big crash and hurt his back in a pileup, landing on the pedal of another bike.On Friday, Armstrong finished 3 minutes 27 seconds ahead of Hamilton, extending his overall lead to 4:22 over the Phonak leader, who was 20th . "I'm a little bit disappointed," said Armstrong. "It's never good for a race when a big rider abandons. Tyler's a good friend."

Last year, Hamilton rode most of the Tour with a broken collarbone sustained in a crash. He finished fourth and had hopes of winning this year after switching from Team CSC.