Not all the mountain passes in the Oisans are equal: some can be enjoyed as a family on a gentle slope, while others must be earned through expert-level effort. Choosing an ascent that suits your physical condition is the guarantee of having a good time rather than suffering. Here is our guide to finding the right collar for your level, from the casual cyclist to the seasoned climber.
Understanding the difficulty of a mountain pass
Three factors determine the severity of a climb: its length, sa average gradient and his altitude (the air thins above 2,000m). A short but very steep pass like Oz-en-Oisans can be just as grueling as a long, steady climb. To objectively compare them, each of our fact sheets displays an’FIETS index, which combines these metrics into a single figure, along with the kilometre-by-kilometre gradient and estimated times according to your ability level.
Beginner: gentle slopes to build confidence
If you are discovering the mountains, aim for consistency and moderate gradients. The Col d’Ornon (13.6 km at an average gradient of 4.7 %) is perfect for a first mountain pass: the gradient never really gets steep. Even easier to ride, the Col du Lautaret from Briançon (an average of 2.7% over %) is climbed almost without realising it. Finally, the short climb up Besse-en-Oisans allows you to taste the high altitude without clocking up the kilometres.
Intermediate: real climbs on lovely roads
A cut above, the Les Deux Alpes climb (9.5 km at 6.5 %) and the balconies of Villard-Reculas or’Auris offer great climbs on wide, pleasant roads. It's also the right time to tackle the legend: the 21 bends of l’Alpe d'Huez (13.7 km at 8 %) is well within the reach of a regular cyclist who paces themselves well on the first, steepest hairpin bends.
Confirmed: the giants of Oisans
Trained climbers will aim for the high-altitude peaks. The Col du Galibier and, at 2,642 metres, the Col de la Croix de Fer, the Col du Sabot (one of the highest in Isère) or the Lake Besson above Alpe d'Huez require endurance and altitude management. These are big days that need to be seriously prepared for.
Expert: the walls and the challenges
For those who love to suffer, the Oisans holds some formidable slopes. The steep climb of’Oz-en-Oisans (averaging nearly 11 %) and, above all, the wild wall of Villard-Notre-Dame (up to 17 % and its unlit tunnels) leave no room for error when it comes to gear selection. Fans of mixed terrain might even fancy a bit of an adventure Col de Solude, to be done on a gravel bike.
The right gear according to the mountain pass
Whatever your level, having the right gearing changes everything. For steep climbs, opt for a compact chainset and a generous cassette (28 to 34 teeth): it is better to spin a lower gear than to force it and damage your knees. On long high-altitude climbs, always keep something in reserve for the final kilometres, which are often the hardest.
Frequently asked questions
What is the easiest mountain pass in the Oisans?
The Col du Lautaret from Briançon (an average of 2.7 %) and the Col d’Ornon ranking among the most accessible.
What is the hardest mountain pass in the Oisans?
Down the slope, Villard-Notre-Dame (up to 17 %); in terms of scale, the Galibier from Oisans and the Col du Sabot.
How do I know if a mountain pass is within my reach?
Use the FIETS index, average gradient and estimated times shown on each mountain pass data sheet to make an informed choice.
Over to you: compare all the climbs on the Oisans mountain passes page, and if you like challenges, discover the’Oisans Col Series.