In Savoie Mont Blanc more than 115 are classified Cycloclimbing Challenges. They have been selected according the official gradient-squared system and the itineraries are over 750 points.

These climbs  are mythical, passes of the Tour de France, such as Galibier, Iseran or Madeleine...

To know more about these Cycloclimbing Challenges click on the french version +info

The gradient-squared system

Passes or climbs are usually evaluated in terms of their height gain, length, average gradient and maximum gradient. All this information can be given on a route profile; however, it is far from easy to objectively compare climbs. The gradient-squared system overcomes this problem.

The principle
The method allocates a score to each climb by adding together the square of the average gradient for each kilometre. The total number of points indicates the physical difficulty of cycling that climb. 

Example one:
HEIGHT GAIN 300 M, LENGTH 5 KM, AVERAGE GRADIENT 6%
Score = (7²x1) + (3.5²x1) + (5.5²x1) +(5²x1) +(9²x1) = 197.5 points

Example two:
SAME HEIGHT GAIN, TOTAL LENGTH AND AVERAGE GRADIENT BUT DIFFERENT GRADIENTS FOR INDIVIDUAL KILOMETRES:
Score = (8²x1) + (8.5²x1) + (11.5²x1) + (0.5²x1) +(1.5²x1) = 271 points

This method reveals that some "minor" climbs are much more difficult than many of the Alps' most prestigious passes. For example, the Signal du Mont du Chat  (above Le Bourget-du-Lac) scores 1224 points, indicating that it is a more difficult climb than the Col du Galibier from Valloire, which scores a "mere" 1183 points!