In short:
- Alpe d’Huez has 21 hairpins over 13.8 km at an average of 8.1% from Le Bourg-d’Oisans.
- The Col du Galibier tops out at 2,642 m, with 18.1 km at 6.9% from Valloire.
- The Col de l’Iseran, at 2,764 m, is the highest paved pass in the Alps.
- High-altitude Alpine climbs can be ridden from late May or June to October.
The must-ride Alpine climbs
The French Alps host the most famous Alpine climbs by bike in cycling. Savoie and Isère hold most of them, less than two hours’ drive from each other.
| Climb | Altitude | Reference side | Distance | Average gradient |
|---|---|---|---|---|
| Alpe d’Huez | 1,850 m | Le Bourg-d’Oisans | 13.8 km | 8.1% |
| Col du Galibier | 2,642 m | Valloire | 18.1 km | 6.9% |
| Col de la Madeleine | 2,000 m | La Chambre | 19.2 km | 7.9% |
| Col de l’Iseran | 2,764 m | Bonneval-sur-Arc | 13.4 km | 7.3% |
When and how to ride them
The best period runs from June to September. The roads over the big passes close in winter and their opening depends on snow.
An early start avoids heat and traffic. Above 2,000 m, the temperature can drop by more than 10 °C between the valley and the summit: a windproof jacket is essential for the descent.
On the equipment side, a climbing or endurance road bike with a compact chainset makes all the difference.
Preparing for the high mountains
Linking two climbs of 1,500 m each requires preparation similar to a sportive training plan. Threshold climbing sessions of 20 to 40 minutes are the most effective.
Riders who prefer gentler scenery will find beautiful loops in the Vosges, described in the guide to Alsace cycling routes.
Frequently asked questions
What are the legendary Alpine climbs to ride by bike?
The most legendary Alpine climbs by bike are Alpe d’Huez (13.8 km at 8.1% with 21 hairpins), the Col du Galibier (2,642 m, 18.1 km at 6.9% from Valloire), the Col de l’Iseran (2,764 m, the highest paved pass in the Alps) and the Col de la Madeleine (2,000 m, around 19 km at nearly 8% from La Chambre). All of them have shaped Tour de France history.
When can you ride the Alpine passes?
High passes such as the Galibier and the Iseran are generally open from late May or June to October, depending on snow. June and September offer the best conditions, with less traffic than July and August.
What gearing do you need for an Alpine climb?
A 50x34 compact chainset paired with an 11-32 or 11-34 cassette lets most riders climb 8 to 10% gradients at a comfortable cadence.