#TDF13: first showdown for Yellow

After a fascinating first week of the 100th Tour we have now reached the first showdown in the high mountains – the first of two stages in the Pyrenées. Sometimes the first mountain stage proves to have a decisive impact on the race; sometimes it doesn't quite live up to its billing. Last year the first mountain stage to La Planche des Belles Filles proved to be decisive for Wiggins. He took the Yellow Jersey and kept it all the way to Paris. 

Will today's stage to Ax-3 Domaines establish the eventual winner? I have my doubts but it should show up anyone who has looked promising so far but in fact does not have the form to be a real contender. Making the transition from the relative flat to long mountain climbs often catches out a few riders, although this year there have already been two hilly stages in Corsica and a lumpy one to Albi. So all rather different from a series of flat stages across Northern France before hitting the Alps as has been the case in some years.

The performance of Andy Schleck will be closely scrutinised. Is Andy Schleck returning to his previous form or will it fall apart once the high mountains are reached? Today's stage should gives us some idea.

We'll be following the action on Steephill.