Col du Glandon is a high mountain pass at an elevation of 1.924m (6,312ft) above the sea level, located in the Dauphiné Alps in Savoie, France. It’s one of the toughest climbs in the French Alps.
The road to the summit is paved. It's called D927 and it links Le Bourg-d'Oisans to La Chambre. This is the first climb and descent that is used in La Marmotte sportive every July. This road can be closed anytime when the access is not cleared of snow. It’s normally closed from the beginning of November to mid May. The col de Glandon is a straightforward col with a gradient that increases near the summit with the last seven kilometres being the toughest on the whole climb. The last two kilometres are over ten percent with stretches of 12 percent.
There are 2 routes to reach the summit. Starting from Barrage du Verney, the ascent is 24.12 km long. Over this distance, the elevation gain is 1.152 meters. The average percentage is 4.8 %. And starting from La Chambre, the ascent is 21.3 km long. Over this distance, the elevation gain is 1.472 meters. The average percentage is 6.9 %. The Col du Glandon was openend in 1898 and was first used in the Tour de France in 1947. Since then it has been used many times.