by Ryland James

VITTEL, France, July 16, 2009 (AFP) – Lance Armstrong has warned the 13th stage of the Tour de France Friday could be a source of trouble when the riders tackle the 8.7km-long Col du Platzerwasel’s monster climb.

On paper, the 200km hilly ride from Vittel to Colmar looks easy compared to some of the mammoth climbs during a three-day spell in the Alps which starts Sunday.

But Armstrong says the Platzerwasel, whose summit is 62km from the finish, will sort the men from the boys.

“The climb up Col du Platzerwasel will be difficult, it is a long way and it will be a real stage,” said Armstrong prior to the start of the 12th stage Thursday, before which he sat third overall at 8sec.

“It is a longer day and anything can happen.

“I know the area, but not that particular climb.”

Featuring only 30km of climbing over five hilltop passes, the stage has been designed to make some riders think twice about shrugging off the difficulty of the climbs in the Vosges.

The Col du Platzerwasel is a category one beast with an average gradient of a punishing 7.6 percent. Some sections near the bottom are over nine percent. The climb could be made tougher if rain falls, as predicted.

And cancer-survivor Armstrong admitted having some concerns following Wednesday’s crash after 27kms which saw several riders tumble to the tarmac.

“It is something which keeps you up at night, you have to constantly pay attention, I try to give myself a bit of space from people in front of me so I have a bit of time to brake,” said Armstrong, who broke his collarbone in a crash in a race in Spain last March.

While Armstrong is only 8sec behind Italian yellow jersey holder Rinaldo Nocentini, Astana teammate Alberto Contador is two seconds ahead of him in second overall.

A bunch of challengers who have far more time to make up – Australian Cadel Evans (3:07), defending champion Carlos Sastre (2:52), Luxemburger Andy Schleck (1:49) and Russian Denis Menchov (5:17) – could use the stage to try and close their deficits.

“You have to watch all the rivals, even someone like Menchov,” added Armstrong.

“Some might say he is five or six minutes behind and his race is finished, but if he gains back time he has the Alps and then if he is close enough on the (Mont) Ventoux, he could present a problem.

“I would put Carlos (Sastre), the Schleck brothers (Andy and Frank) and
(Cadel) Evans in the most dangerous category and then the others are just behind.”