The north side of this famous Tour de France pass is the hardest, so you have a good excuse for taking a break to visit the Charterhouse at Le Reposoir before tackling the steepest part of the climb.
Slightly steep gradients towards the start, varying from 6 to 8% for 4 km, and then the final assault around 4 km from the pass, with a tough mountainside road and a percentage of 10% recorded over the last 1,500 straight metres.