Cancellara of Team Saxo Bank overtook France’s Sylvain Chavanel. Armstrong lost time after a puncture and fell behind defending champion Alberto Contador. Frank Schleck, fifth overall last year, quit after a fall.
Eight miles near the end of the 132-mile stage between Wanze in Belgium and Arenberg Porte du Hainaut, France, were over cobblestones, following part of the route of the Paris- Roubaix one-day race known as the “Hell of the North.”
“I was really motivated,” Hushovd told Eurosport. “It was like a mini Roubaix.”
Seven-time champion Armstrong, who’s riding his last Tour, dropped to 18th from fifth and is 2 minutes, 30 seconds off the lead, according to provisional standings. Cancellara leads by 23 seconds from Britain’s Geraint Thomas, while two-time runner-up Cadel Evans of Australia is third.
Schleck fell on cobblestones with about 20 miles left. His younger brother Andy, who also rides for Team Saxo Bank, stayed out of trouble and rose to sixth overall.
Armstrong lost ground with about 10 miles left. Television footage showed him riding a bike with one tire thicker than the other after an apparent wheel change. He wrested back some time by following the rear wheel of RadioShack teammate Yaroslav Popovych and then going solo.
Contador appeared to slow because of a tire problem over the last mile. He dropped to ninth from seventh overall and is 1 minute, 40 seconds off the lead.
Chavanel had punctures with about 10 miles and six miles left and threw his bike into a grass bank on the second occasion as he saw his race lead slip away.