I found this article on climb category classifications, but was wondering if anyone might have other, more detailed information on climb categories.


http://www.adcc.asn.au/index.php?opt...=article&id=75

This articles says:

How do the organizers of the Grand Tours evaluate the ratings for the climbs in their races?

The Tour organizers use three criteria:

(1) The length and steepness of the climb
(2) The position of the climb in the stage
(3) The quality of the road surface

General guidelines for classification are as follows:
Hors Category (HC) - the hardest, climbs of 5000ft+(1500m+)
1st Category - climbs of 3500-5000ft (1100-1500m)
2nd Category - climbs of 2000-3500 ft (600-1100m)
3rd Category - climbs of 1000-2000 feet (300-600m).
4th Category - the lowest category, climbs of 300-1000 feet (100-300m).


Although it says that the first consideration is the length and steepness of the climb, the explanation above doesn't really explain the length factor. For example, a climb with300 metres of elevation over 3 km would be an average of a 10% grade (a decent climb - probably a Category 3). But a climb with 300 metres of elevation over 30 km would be an average of a 1% (a barely noticable climb - no category at all).