Col de Sarenne is a high mountain pass, at an elevation of 1.999m (6,558ft) above the sea level, located in the Central French Alps, in the commune of Huez, in the Isère département in the Rhône-Alpes region. The road over the pass is old, bad and narrow, without guardrails. A mistake could see you falling straight down 30 metres.
Above the famous Alpe d'Huez there are 2 climbs that can be ridden. One is Col de Poutran. The other is the Col de Sarenne. The road to reach this pass is located leaving the village of Alpe d'Huez, and the quality of the road is extremely poor. The road over the pass is asphalted, but there are some sections with gravel parts especially along the sides of the road. The road is called Route du Col de Sarenne and links Alpe d'Huez with the villages of Mizoën and Le Freney-d'Oisans in the Romanche valley. It’s closed from end of october to early june, and runs parallel to GR54 (French long-distance trail) for most of the way.
There are 3 possible routes to reach this pass. From Bourg d'Oisans, the ascent is 21.2 km long. Over this distance, the elevation gain is 1.282 meters. The average percentage is 6 %. From the crossroad of Col de Sarenne, the ascent is 12.76 km long. Over this distance, the elevation gain is 954 meters. The average percentage is 7.5 %. And from Le Freney d'Oisans, the ascent is 19.5 km long. Over this distance, the elevation gain is 1.071 meters. The average percentage is 5.5 %.
There is a restaurant on the top of the mountain. The pass has been used by the Tour de France race. The road is not for the faint hearted with steep drops and a few sections of unpaved road to challenge even the most experienced cyclist. The road over the pass is narrow and undulating. It is a beautiful road that although close to civilization feels really quite remote, partly due to the fact that parts of the road are a little rough and partly because it can be very quiet. Once at the top of the Col de Sarenne there is a huge technical switchback road descent down to the Barage du Chambon at the foot of Les Deux Alpes.