September 12, Stage 20: San Lorenzo de El Escorial - Cercedilla 181 km

The climbing concludes in traditional fashion with a tough stage through the sierra, north of Madrid.

The four first-category climbs aren’t particularly severe individually but could become so if the GC is still in the balance and one or more teams decide to race hard before the final ascent. The roads are good and the descents fast, particularly on the Navacerrada, which features twice. The peloton will tackle the northern and southern flanks of the Morcuera, then the Puerto de Cotos, where there are 7km of flat before they drop down the Navacerrada into the finish at Cercedilla.

It’s not ridiculously hard, which might tempt some well-placed riders into a long-range assault.

David López (Team Sky rider):

"As usual, the organisers will be hoping that the race comes down to this stage. The riders know these climbs very well and it’s sure to bring out the final contest between the main favourites, who will find this a long stage having already done so much climbing."

The text in this preview originally appeared in the September edition of Procycling magazine.