Three-time Tour de France winner Alberto Contador of Spain, center, Andy Schleck of Luxembourg, left, and Cadel Evans of Australia, right, are closing in on Thomas Voeckler as the three-day Alps portion of the Tour de France is underway. (Laurent Rebours/AP)

On Wednesday riders began the critical three-day stretch in the Alps where Voeckler’s weaknesses are already being exposed. He lost 27 seconds on his lead in the 17th stage but retained the yellow jersey and a 1 minute, 18 second lead over Australian Cadel Evans.

Meantime, defending champion Alberto Contador continues to struggle to gain significant ground on the riders atop the leaderboard. Contador currently sits in sixth place, 3:15 behind Voeckler. His struggles with an injured right knee have been well-documented, and after making up time Tuesday, Contador gained no ground on the other four riders ahead of him Wednesday — Evans, Frank and Andy Schleck and Samuel Sanchez — despite multiple attempts to break away from the pack.

All along Voeckler has said his lead won’t hold up — especially not if he continues to run off the road as he did Wednesday. He’s gone so far as to say he has a “zero percent chance” of becoming the first Tour winner from France since Brenard Hinault in 1985.

So who’s the favorite heading into the home stretch? It seems to be anyone’s guess, but Evans will looking over his shoulder to keep an eye on the three-time champion.

“I’ve got a good advantage over Alberto now, but Alberto has shown in years gone by what he can do when he’s really at his top.”

Contador hopes his experience in the Alps will pay off, and he’s well aware the time to make a move is nigh.

“The climbs in the Alps are different than the Pyrenees, they are longer and at a higher altitude. Some riders will suffer from that. But we need to attack, that’s for sure.”

The journey through the Alps continues Thursday with a 200 kilometer climb from Pinerolo to Galibier Serre-Chevalier.