Port de Pailheres is one of the nicest climbs in the Pyrenees. A bit out of the way of the more known climbs in the central Pyrenees, Port de Pailheres is an amazing climb, also with personality. It starts with very steep slopes in a long stretch of the road, then we have a very nice part with many switchbacks very close to each other, and finally a superb scenic road for the last 3 km.

Numbers do not lie, this is a very tough climb. 1200 mts elevation for 15,4 km, that gives an average 7,3% gradient. Tough, very tough, including passages at 10%, 11%, 12%… You can see the elevation profile on the right. This is a really serious climb getting over 2000 mts (just 2001!).
Pailheres is one of those climbs that you have to include in your bike tours in the Pyrenees. A narrow solitaire road with no traffic at all. It is just perfect for cycling.
Pailheres in Tour de France
Port de Pailheres has been included in the Tour de France route 5 times so far, in 2003, 2005, 2007, 2010 and 2013. In all these years, Port de Pailheres was the last but one climb in the stage and was always climbed by the eastern side starting at Usson Les Bain. Its privileged location, arriving to Ax Les Thermes, permits a final climb to Plateau de Bonascre (Ax 3 Domains) or Plateau de Beille.

Let me recommend a very nice loop in which you can include Port de Pailheres and also Col de Pradel, a not-so-steep climb in a tiny solitaire road getting to 1680 mts. loop about 85 km long is really nice, but watch out, almost 2500 mts elevation!
https://www.strava.com/activities/1774052101
Also, there is another very nice loop that we can recommend. Starting at Ax Les Thermes, you can take the road to Col de Chioula, then descend to Rodome, and then take to Mijanes and climb to Pailheres (always recommended to climb from this side as the Ax Les Thermes side is not so nice). This tour is 81 km long and 2600 mts elevation, also a demanding and a very nice ride!