Full-blown uphill mountain time trials, like Friday's 10.9-kilometre climb to the Peyragudes altiport in the Pyrenees, are comparatively rare beasts in the Tour de France. But when they do put in an appearance, they can be the key ingredient to taking yellow in Paris.
The most famous case of a Tour mountain TT doing exactly that was in 1959, when Federico Martín Bahamontes, aka 'The Eagle of Toledo', destroyed the field on a 12.5-kilometre ascent of the never-ending loops and zig-zags up the Pûy de Dome in the Massif Central mountains.
