Col de Sarenne: Cycling Climb

The climb · France

About Col de Sarenne

Above the Lac du Chambon dam, the road turns uphill for Mizoën and the Ferrand valley. This is the eastern approach to Col de Sarenne, following the D25 and D25a through Clavans towards the pass. The selected ascent is about 12.9 kilometres long, averaging 7%, and the combination gives it the substance of a major climb even before the upper slopes come into view.

The valley villages provide landmarks along the way, but the road's character changes as it gains height towards the open ground around the col. The settlement gives way to a more exposed mountain setting, with the final approach carrying the ride out of the lower valley altogether. The top is the pass itself, before the road continues towards Alpe d’Huez. Coming from the dam, Sarenne feels like a complete ascent in its own right, with a convincing progression from village road to high crossing.

01 / The ascent

Elevation profile

Start 1,024 m · Summit 1,929 m

Gradient by distance12.92 km / 925 m gain

0 km2.6 km5.1 km7.7 km10.2 km12.8 km

02 / The crux

Where it gets difficult

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

Steepest 500 m average

11.5%

Where to find it

0.10–0.60 km from start

Net height gained: 58 m
Section length: 500 m

The whole climb12.75 km

0 kmFinish

03 / The numbers

Climb statistics

Distance: 12.92 km
Elevation gain: 925 m
Average gradient: 7.0%
Climb category: HC
Start elevation: 1,024 m
Summit elevation: 1,929 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

1 h 4 min

Power throughout: 225 W
Average speed: 12.0 km/h

Based on the 12.75 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