Col du Mont-Cenis: Cycling Climb

The climb · France

About Col du Mont-Cenis

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Simon Warren’s 100 Greatest Cycling Climbs of the Tour de France

From Lanslebourg, the Col du Mont-Cenis lifts you out of the Haute Maurienne towards a broad high pass. The bends gain height above the valley, turning a relatively compact ascent into a convincing mountain ride. About ten kilometres at an average near seven per cent is enough to ask for your full attention.

The pass comes before the great Mont-Cenis lake when you approach from this side; do not mistake the waters farther on for the climbing finish. There is ample reward in reaching the col itself, where the journey opens into high country. Mont-Cenis has the scale of a major Alpine crossing without requiring you to ride its entire international route.

01 / The ascent

Elevation profile

Start 1,404 m · Summit 2,090 m

Gradient by distance9.78 km / 687 m gain

0 km2 km3.9 km5.9 km7.8 km9.8 km

02 / The crux

Where it gets difficult

Choose a distance to find the steepest continuous section of the climb.

Steepest 500 m average

12.2%

Where to find it

8.30–8.80 km from start

Net height gained: 61 m
Section length: 500 m

The whole climb9.78 km

0 kmFinish

03 / The numbers

Climb statistics

Distance: 9.78 km
Elevation gain: 687 m
Average gradient: 7.0%
Climb category: 1
Start elevation: 1,404 m
Summit elevation: 2,090 m

Current weather

At the climb start

Loading weather…

Weather data: MET Norway

04 / Your effort

How long would it take?

Enter the power you could hold for the whole climb. We calculate a moving time from the elevation profile and the forces you ride against.

Sustained power

W/kg

Use your intended climbing effort, rather than FTP unless you can hold it for the predicted duration.

Rider weight (kg)

Bike + kit weight (kg)

Bike + kit includes clothing, bottles and luggage.

Advanced settings

Defaults represent a road-bike scenario. Adjust these settings to match your tyres, drivetrain and riding position.

Effective drag area (CdA) (m²)

Rolling resistance (Crr)

Drivetrain efficiency (%)

Modelled moving time

47 min

Power throughout: 225 W
Average speed: 12.4 km/h

Based on the 9.78 km elevation profile. Assumes steady power, with no stops, braking or drafting. Rounded to the nearest minute.

The science behind the calculation

For each part of the stored profile, we solve the steady-state cycling power equation for speed, then add distance ÷ speed across the climb. Gravity uses rider + equipment weight; available power is W/kg × rider weight. This uses the profile’s distance and elevation together, without mixing in another route’s metrics.

Power × efficiency = gravity + rolling resistance + air resistance + bearing losses

The resistance equations are adapted from Martin et al. (1998), Validation of a Mathematical Model for Road Cycling Power. Air density changes with profile altitude using NASA’s standard-atmosphere model. This calculator’s adaptation has not been independently validated.

It predicts travel at the power you enter, including on descents. It does not model acceleration, cornering, braking, traffic, wind, changing weather or fatigue. At altitude, choose power you can sustain there: thinner air reduces drag, but this model does not predict its effect on your ability to produce power. Profile quality and assumed equipment settings also affect the result.

05 / On the ground