The Grand Som trail (Chartreuse, Isère)

Duration : 1 day

France, Northern Alps

Level : from intermediate to advanced

from 52 € / p. from 3 to 6 persons

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Come and run in the heart of the Chartreuse massif for a day, to discover wild landscapes and a unique cultural heritage.

This pre-Alpine massif between Isère and Savoie with its high plateaus, its easily accessible summits and its protected forests is an ideal terrain for trail running.

During this day, I propose a wild and spectacular course in the heart of the natural park. At the rhythm of running and fast walking we will climb two mythical summits of Chartreuse, the Petit Som and the Grand Som. Our exploration will also lead us to the discovery of the Grande Chartreuse Monastery, a true encounter with preserved nature and its history.

From Saint-Pierre-de-Chartreuse we will make a gradual and gentle ascent to the Monastère de la Grande Chartreuse. Here you will be able to see our goal of the day, the Grand Som. A not very technical path, first in the forest and then through the meadows, will take us to the Col de la Ruchère and then to the more technical and vertiginous passage to the Petit and Grand Som. The steep descent with some tricky passages in the first parts will allow us to tackle the techniques of descent and the postures to gain in efficiency. The second part is more fun and easy, with a series of switchbacks that will take us on a majestic balcony path before descending into the valley to the starting point.

This day is open to people who regularly run (2/3 times a week) or who have experience of long hikes on sometimes technical terrain.

Intensity: moderate.
Technicality: sometimes demanding terrain (occasional passage of scree, ridges, steep slopes).
Pre-requisites: you run regularly several times a week and/or you practice endurance sports (trail, cycling, hiking, etc).
In summary: 21 kilometres and 1350 meters of positive and negative altitude difference. Up to 7 hours in the mountains (including breaks).

Equipment to bring for the day:

  • A 5 to 15 litres backpack.
  • A waterproof or windproof jacket.
  • A long-sleeved technical T-shirt.
  • Leggings in the backpack.
  • Socks suitable for running.
  • Sunglasses.
  • A plastic bag for waste.

If you want to improve your skills before embarking on this trail, I recommend this trail discovery course, also in Chartreuse.


  • Welcome at 9.15am in Saint-Pierre-de-Chartreuse (or 8.30am in Grenoble).
  • 10am - 4.30pm: hike/run to the Grand Som with picnic in the mountains.
    • Management of effort according to the terrain.
    • Techniques for moving downhill and uphill.
    • Use of poles.
  • 4.30pm - 5pm: stretching and debriefing.
  • End of the day at 5pm in Saint-Pierre-de-Chartreuse or at 5.45pm at Grenoble train station.

The price includes

  • Supervision by the mountain leader specialized in trail running.
  • Personalized coaching: analysis of objectives and development of individual training plans on request.
  • Civil liability insurance.

The price does not include

  • Transport to the meeting point and from the end of the tour.
  • Lunch (picnic).
  • Drinks.
  • Anything not mentioned in "The price includes".
Next departures :

No scheduled departure, but you can contact me to book your dates.

Infos & Booking