Beautiful mountains and some great cycling.
Thanks to the guys at Cycols for suggesting this loop. For better photos than mine and a (French) description of the loop in the opposite direction see here.
This was the hardest route I have done in a few weeks. As the profiles above show, each of the four main climbs have some long steep stretches. But they are all on beautiful, quiet roads.
The first climb, Col de Marcieu heads up to a sort of plateau between the high peaks on one side and the plain below. Very nice. After descending (and convincing some work men to let me cross a closed bridge), I joined the route up the east side of Col du Granier. Chatting with some locals they had warned me this was steep. No lie. Very uneven with a few nasty ramps.
At Col du Granier, I refueled with water and a tasty bacon-cheese omelette.
Descending the south side of Granier, the route rides through the center of the Chartreuse region. Lovely. With some very nice villages – St Pierre-de-Chartreuse looked particularly charming.
Col du Cucheron is the least interesting of the 4 climbs – a straightish drag – or maybe I was just feeling tired.
This stretch of the route through the centre of the Chartreuse has appeared many times in pro races like the Tour de France, The Dauphiné, etc. But usually it includes Col de Porte on the way to/from Grenoble.
As the road started climbing to Col de Porte I turned off onto a tiny road up the west side of Col du Coq. It was the worst surface of the loop, but no problem for climbing at my speed. Again, some scarily steep ramps, but a superb climb up through the woods and finally over the top, for a hair-raising descent back to the start.
The other – east – side of Col du Coq is a very tough and interesting climb. Details here.
Hard work, but I can’t recommend this loop enough.