French Alps, France · from Bonneval-sur-Arc
Col de l'Iseran
The Iseran from Bonneval-sur-Arc is the roof of European road cycling: the highest paved through-pass in the Alps, climbing steadily through the Vanoise national park scenery to 2,770 m. The gradient is honest rather than vicious — the altitude does the real damage.
Summit elevation: 2770 m
How fast would you climb Col de l'Iseran?
Enter your power and weight. A physics engine calculates your estimated time against the gradient profile.
Predict your
performance.
See how power and weight affect your time on a real climb.
*Demo simulation uses standard road bike physics (CdA 0.32, Crr 0.004).
Col de l'Iseran and the Tour
First crossed by the Tour in 1938, the Iseran has been the highest point of the race whenever it features. The road was built in the 1930s as part of the Route des Grandes Alpes.
In 2019 the Tour's decisive moment happened here: Egan Bernal attacked over the summit before a hailstorm stopped the stage on the descent, freezing the gaps and effectively handing him the yellow jersey.
Get a km-by-km pacing guideRiding it yourself
When to go
One of the shortest seasons of any famous climb — typically mid-June to early October. Even in August, summit temperatures can approach freezing; never descend without full layers.
Base & logistics
Bonneval-sur-Arc, one of France's prettiest villages, is the base for this shorter, wilder side; Val d'Isère serves the northern approach. No services between Bonneval and the summit. Combine with the Col de la Madeleine or Mont Cenis for a Maurienne block.
FAQ
How long is the Col de l'Iseran climb?
From Bonneval-sur-Arc, the climb is about 13.1 km with roughly 963 m of elevation gain at 7.4% average gradient (based on the simplified profile used by this simulator; published figures vary slightly by source).
How long does it take to cycle up Col de l'Iseran?
It depends almost entirely on your power-to-weight ratio. Use the simulator on this page: enter your FTP and weight, and a physics model (air resistance, rolling resistance, gravity) estimates your time on the gradient profile.
How accurate is the time simulation?
The simulator uses a simplified segment profile and standard road bike assumptions (CdA 0.32, Crr 0.004, 8 kg bike). It does not model wind, drafting, altitude, surface or pacing errors, so treat the result as a realistic estimate, not a guarantee.
How should I train for Col de l'Iseran?
Sustained climbs reward steady threshold and sweet spot work plus a power-to-weight improvement over weeks, not days. TrainCraft builds structured cycling training plans and adapts them when you miss sessions, using fatigue science (CTL/ATL/TSB).
More famous climbs
Preparing for this climb?
A climb like this is won weeks in advance. TrainCraft builds a structured plan around your FTP and available hours, and adapts it when you miss a workout.
Start Training FreeThe profile is simplified into 15 segments for simulation; real gradients vary metre by metre. Stats shown are derived from this simulated profile and closely match commonly published figures. Time estimates assume standard road bike physics and no wind.
Training for a climb like this?
TrainCraft builds structured training plans and adapts them when life gets in the way — real fatigue science (CTL/ATL/TSB), visual workout builder, Strava & Garmin sync. Free to start.