La Rosière: Cycling Climb

The climb · France

About La Rosière

I start from the valley, the road rising with an easy grace. Gradients slowly stiffen, teasing my legs into effort. Alpine pastures and distant peaks come into view as the climb unfolds. The air smells of pine and summer flowers. La Rosière isn’t aggressive; it encourages a steady pace, rewarding focus and stamina. The summit is quiet, with sweeping views of the surrounding Savoie region.

01 / The ascent

Elevation profile

Start 907 m · Summit 1,785 m

Gradient by distance15.86 km / 878 m gain

0 km3.2 km6.3 km9.5 km12.7 km15.9 km

02 / The crux

Where it gets difficult

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

Steepest 500 m average

10.0%

Where to find it

11.00–11.50 km from start

Net height gained: 50 m
Section length: 500 m

The whole climb15.86 km

0 kmFinish

03 / The numbers

Climb statistics

Distance: 15.86 km
Elevation gain: 878 m
Average gradient: 5.5%
Climb category: HC
Start elevation: 907 m
Summit elevation: 1,785 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: 15.0 km/h

Based on the 15.86 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