BARCELONNETTE, France – Simon Geschke of the Giant-Alpecin team won a tough and dangerous Stage 17 of the Tour de France in the Alps on Wednesday with a brave solo ride, while former champion Alberto Contador fell during a terrifying high-speed descent.

Race leader Chris Froome staved off multiple attacks to get through the first of four days in the Alps unscathed. He showed great bike-handling skills on the 10-mile descent from the Col d’Allos mountain pass, where he hit speeds of 40 mph on the twisting, narrow bends.

Geschke was first down that slope, having ridden off ahead with 30 miles still to go.

Showing how tricky the descent was, French rider Thibaut Pinot hit the deck when his wheels slipped from under him on a left-hand bend.

“It was really challenging,” said Geschke, whose stage win was the fifth by a German rider on this Tour and ideal for an event that is back on public TV in Germany after a hiatus of several years.

“I just tried to go down there as fast as possible and stay on the bike, which was not easy.”

Contador’s shorts were torn in his crash on the descent, and the 2007 and 2009 champion was forced to swap bikes with teammate Peter Sagan, costing him time. He rode in more than two minutes after Froome.

While the Spaniard stayed in fifth place, the Tinkoff-Saxo leader who was hoping to add the Tour to his Giro d’Italia win in May is now a substantial six minutes and 40 seconds behind the Team Sky rider overall.

Froome and Nairo Quintana sprinted together for the line on the final ascent to the Pra Loup ski station, with the Colombian just beating the Briton this time.

Quintana is still second overall, with his 3:10 deficit to Froome unchanged. But Quintana was very active on the stage with five climbs, testing Froome with bursts of speed that the 2013 winner was forced to match, having identified the 2013 runner-up as his biggest rival again this year.

With time running out for podium contenders to claw back a few minutes, Froome is expecting more attacks in the next three days of progressively harder Alpine climbing before the largely ceremonial ride into Paris on Sunday.

“My rivals are going to take bigger risks,”Froome said. “We are seeing an all-or-nothing approach.”

Tejay van Garderen, who had been third at the start of the 100-mile stage from Digne-Les-Bains, abandoned with a headache and feeling out of energy after battling a respiratory infection for several days, his team doctor explained.

Alejandro Valverde, Quintana’s Spanish teammate on the Movistar team and who is riding strongly, moved up from fourth to third overall, 4:09 behind Froome.

Froome’s Sky teammate Geraint Thomas moved up from sixth to fourth, vaulting over Contador, and is 6:34 behind his team leader.

“The best day of my life as a rider,” Geschke said after holding off Andrew Talansky, the Cannondale-Garmin rider who was in hot pursuit on the final climb.

“Just ran out of road,” said Talansky, who took second in the stage, 32 seconds behind. “Geschke just had a bit too much time coming into that final climb.”

Riding solo for over an hour from such a long way out, up the two final climbs and alone down the hairy descent was risky. But Geschke said he knew that other riders in his group were stronger climbers than him, so he decided to shake them off as early as he could.

“I took the only chance I had,” he said. “I thought, ‘OK. If it doesn’t work out, it doesn’t work out.”’

He added: “It’s incredible it worked out.”