Col de la Croix de Fer from Bourg-d'Oisans
Road cycling
- Distance
- 38.9 km
- Elevation
- 1,570 m
- Est. time
- 2 h 20
- Power
- 220 W
- Max altitude
- 2,058 m
- Avg gradient
- 3.4%
The climb: 32.1 km averaging 4.2% with a few descents, 12% at its steepest, 1,565 m of elevation gain, from Rochetaillée to the col.
Time and power estimated for a 75 kg rider at 220 W, climbing without stopping. Route from OpenStreetMap, altitudes from Copernicus.
The great Oisans classic, starting from Le Cosy Lodge. Seven flat kilometres to Rochetaillée, then Allemond, where two hairpins lead up to the Verney dam. The road runs along the lake and climbs steeply, in the shade of the trees, to Le Rivier d'Allemond. A short descent, then the Maupas straight, the hardest part of the day. Past the Grand'Maison dam, you climb in the open through the high pastures, pass close to the Col du Glandon and finish at 2,067 m, beside the iron cross that gives the col its name, facing the Aiguilles d'Arves. Long and irregular, it's a true hors catégorie climb.
- Hors catégorie, in the Tour de France since 1947
- 2026 Tour: Carapaz first over the top, on a stage starting in Bourg d'Oisans
- The Verney and Grand'Maison lakes, iron cross at 2,067 m
- Summer
- Road rideable from June to October, weather permitting.
- Winter
- Closed in winter · reopens in June
Set off early with two bottles: there's water at Allemond, Le Rivier d'Allemond and the col, but the top section is in full sun. On the way back, the Maupas descent is steep and tight, and there's a short climb back up towards Le Rivier before you drop down to Allemond.
About 6 km on the D1091, the Grenoble road, which is very busy in summer (lorries, motorhomes). The Oisans greenway also reaches Allemond, but its route changed after the 2024 storms: check with the tourist office that it's open. The D526 is closed in winter on the Isère side (it reopened on 29 May in 2026), and the road may be closed on the morning of some events, such as the Marmotte in late June.