Definition of climb categories

[TimO]

Every year I hear about the various category of climbs in the Tour, including all the famous Hors Categorie climbs, but I've singularly failed to find a definition of what is a Cat 1,2,3,4 and HC climb.

Is there an actual rigorous definition, or does someone look at the climb, suck wind through their teeth and say "Umm, OK this one looks like a Cat 2..." ?

[Greenbank]

I looked this up the other day...

There's no hard and fast defintion:-

VeloNews | A guide to scoring the jerseys | The Journal of Competitive Cycling.

"
Climbs in the Tour are classified in five somewhat arbitrary categories:

CAT. 4 Usually less than 3km in length, an easy pitch that amounts to no more than a sustained rise in the road
CAT. 3 Slightly harder, up to 5km in length
CAT. 2 Between 5km and 10km, and steeper than a 4-percent grade
CAT. 1 Long and steep. Between 10km and 20km, and steeper than a 5-percent grade.
HORS CATEGORIE (HC) or above category. The longest, steepest mountain climbs. Extremely difficult climbs, sometimes 15km to 20km, with grades exceeding 10 percent.
"

[David Martin]

I think they were originally graded as the hardest gear an aging citroen car could get over the hill in.

So cat 4 - 4th gear, cat 1 - first gear. HC - get out an dpush and you'll be lucky to make it.

Dating from when most of the roads were rough tracks.

..d

[Bigdaveskinnytyre]

It varies a bit, some of the 4th Cat climbs the tour went over in Kent are under 3Km but have pitches over 10%, so the ageing citroen may have to drop to 2nd but not for long.

[MSeries]

I think they were originally graded as the hardest gear an aging citroen car could get over the hill in.

So cat 4 - 4th gear, cat 1 - first gear. HC - get out an dpush and you'll be lucky to make it.

Dating from when most of the roads were rough tracks.

..d

HC was hors categorie, not classified, because the test car didn't make it

[Greenbank]

Put it this way, for new climbs they don't lay down some gravel and see what gear a 2CV needs to scrape its way up the hill.

It's all subjective decisions by the route planning committee(s):-
* 4.5km but steeper than a Cat 4, d'accord, Cat 3.
* 35km long but only 2-3%, not an HC climb.
..etc..

[Frenchie]

... would have been a Traction Avant.

[LittleWheelsandBig]

Historically, the same mountain could get a different classification from year to year, depending on whether it is early or late in the stage and how much climbing has occurred on that stage beforehand.

[gonzo]

I'd heard that HC meant that the car had to go up in reverse as there's more toruqe that way.

[clarion]

I thought a TA only had three forward gears