Col Du Glandon from the South
From Bourg D’Oisans, there is a little over 10 km of flat valley riding before you hit the bottom of the climb for real, shortly after the town of Allemont. This inital part is fairly steep (10 - 11%) and continues on for a kilometre or so before easing off a little to a gradient which varies between 6 - 10%. The road then passes through the town of Rivier D’Allemont - you can fill up water bottles here - before a short but steep descent where the road crosses a river. Immediately after this, the road pitches up again to the steepest part of the climb - 11 to 12%. From then on, after a tiny downhill section, the road consistently climbs up to the Barrage de Grand Maison, a large dam and lake which is the source of the largest hydro-electric facility in France (you will have ridden past the power station at the bottom of the climb). The road then flattens out, and the valley widens once you climb past the lake. It is in this grassy area where if you keep your eyes peeled above and below you can spot marmottes - although you’ll often hear them squeaking before you see them! After another downhill (longer this time) you’re onto the last 3 km of climbing. The top of the Col du Glandon is a few hundred meters after a turning to the left (signposted) - if you continue on rather than turning you will be heading towards the summit of the Col de la Croix de Fer.
From the top of the Col you often have a clear view 90 km away of Mont Blanc,the highest mountain in Europe.
Great scenery.....and a chance to spot marmottes during the latter part of the climb as they can sometimes be seen in spring and early summer out foraging for food, or later on in the season sunbathing on rocks.
The Col du Glandon is a varied climb with a range of slopes - not relentless like Alpe D’huez, and not as long as the Col du Galibier at 31 km but some think it is harder than both! The climb from the south side is the first col tackled each year in the sportive, La Marmotte. The ascent from the north side is probably a tougher climb however - as it is shorter and steeper, coming from the Maurienne valley. Both routes offer great scenery - a ‘must do’ ride during your stay in Bourg D’Oisans.
Col Du Glandon from the North
From the north, the climb starts behind a town called St Etienne de Cuines (the start of the Col du Madeleine is only a few kilometres to the north of here). This climb can be boiled down to a ride of two halves, with a sting in the tail!
For the first part of the climb the road is fairly consistently between 7 - 8% for 8 kilometres. There are some picturesque streams following the winding road as you pass through the forest. Then the road flattens off and passes through the small ski village of St Columban des Villards, a good place to take a break if you need one - the hard work is still to come!
After leaving the village, the roads heads up again and gets a little steeper (around 9%) before easing off again after 5 km. Don’t let this fool you into a false sense of security though - even though you can see the trough in the mountains where the summit of the col is heading, after a short time the last set of switchbacks appear, and the last two kilometres are at 11%! You’ll really find out here whether you left enough in the tank....if not prepare to grind up this last part at a snails pace!