KmM = Kilometer Marker
Read this page for a lot of background information about cycling in the French Alps.
13 km, 1,072 meters of climbing. The icon of icons – the most famous climb in the world. 21 switchbacks, steep from the gun, and beautiful views of the road above as you get higher. If you are in the area you have to ride it. The natural place to stop is in the town of Alpe d’Huez, with all the stores, bars, and restaurants. The official climb goes on for maybe another 1.4 km, following signs for Itineraire de Tour de France, and finishes at a rather nondescript sign. Enough said.
Update: August 2017. From the top of the Alpe d’Huez climb, you can continue past the airport (Altiport) and over to the Col de Sarenne (about 300 meters of additional climbing, with some 11-12% on the final stretch up to the Col.) Then descend the beautiful switchbacks on the other side to the Barrage du Chambon, cross the dam, then continue down the valley back to Le Bourg-d’Oisans. The whole loop is about 49.7 km with 1,493 meters of climbing, and goes through much more remote and wild country than the climb up Alpe d’Huez. Well worth doing.
Col du Glandon / Col de la Croix de Fer
See the description in the Maurienne Valley page.
Col de Sarenne
About 13 km and 975 meters (3,199 feet) of ascent. The best of the rest. If you’ve done Alpe d’Huez and the Col du Glandon, you’ll be looking for other climbs around Le Bourg-d’Oisans. Of the ones I’ve done, this is the best. I started at the Lac du Chambon dam. Just before the tunnel, which at the time of writing is closed, you head up the valley towards Mizoën. After about 6 km, just as you enter Clavans-le-Haut, you make a very sharp left and start heading up the hillside. Just before 8 km the road becomes a patchwork quilt of repairs, which is okay on the way up, but makes for a rather bumpy ride on the way down. The views become better and better as you climb.
Col du Sabot
About 14.5 km and 1,290 meters (4,232 feet) of climbing. A lesser known – and steep – ride which takes off from the lake at the start of the Col du Glandon and climbs steeply past the town of Vaujany. Just past the next village, La Villette, you’ll come across a surprising sight – tennis courts. At this point the road leaves civilization, the road surface becomes less smooth, and you head up into the wilderness. Eventually the road finishes at a large dirt parking lot at the col.
Les Deux Alpes
About 8.5 km and 590 meters (1,936 feet) of climbing from Lac du Chambon. A steady but uninteresting climb with no views until you finish the ride in the town of Les 2 Alpes and see some impressive mountains in the far background.
Links and Other Clicks
The Oisans Col Series. In 2015 every Tuesday the road up one of the climbs near Bourg d’Oisans will be closed to cars so that cyclists can have the road to themselves.