According to legend, the Tour de France's climbs are categorised by the gear that a Citroën 2CV, the iconically French car, had to use to successfully make it to the top.
Category 4, the lowest categorisation for the easiest hills, was possible in fourth gear; Category 3 in third gear, and so on. Hors Categorie, or 'beyond categorisation' was reserved for those climbs which a 2CV could not drive up.
While it's true that the Deux Chevaux (the name means 'two horses', as in 2hp) was not made for climbing mountains it's probably not true that it was the source of the classifications.
The Tour de France categorisations were created in 1947; at first, the mountains were only divided into first- and second-category climbs, and the HC designation was only introduced in 1975. 2CVs, on the other hand, were not manufactured until 1948 and by 1975 had 602hp at their disposal rather than the 375 they were born with post-war – more of a Trois Chevaux you might say.
More likely it was a Hotchkiss, the car used for years by Tour founder Henri Desgrange, that would be struggling up the climbs and needing gear selection advice. And Alpe d’Huez has always been an HC climb, yet the road is purpose built so that the biggest, heaviest vehicles can deliver their goods or their people to the popular ski resort above.
These days, the classification of an individual climb can change from year to year depending on where it comes and what else is happening in the stage, and its category depends a lot more on how important the organisers want that climb to be in the King of the Mountains competition.
For our Autumn/Winter 2014 photoshoot we took a 2CV Fourgonette van into the high mountains.First, we went to the top of the Cime de la Bonette at dawn, to catch the sunrise on the highest paved road in Europe.
It's only an hour's drive from Nice but it's cold and wild and barren up there, and only a day or two after our visit the first snow was settling on the peaks around it.
Let's call it an Hors Catégorie photoshoot.