Blea Tarn Climb: Cycling Climb

The climb · United Kingdom

About Blea Tarn Climb

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Simon Warren’s Another 100 Greatest Cycling Climbs

Blea Tarn climbs out of Great Langdale by the road beyond the Old Dungeon Ghyll, gaining the hillside towards the tarn. The selected ascent begins on the valley approach, so its early metres are less severe than the bends that follow. That small introduction is soon over: the road turns across the slope and the climbing becomes much more concentrated. At about 1.2 kilometres, this is a short ascent, but the change from valley floor to open hillside feels pronounced.

The middle and upper stretches contain the harder work, with no long easy section before the selected finish. An average near 10.3% reflects that sustained rise. The Langdale Pikes and surrounding crags give the road an unusually strong setting, even when the gradient keeps your attention close to the front wheel. This description follows the northern approach; the road beyond continues towards Blea Tarn. A brief climb with a distinctly Lakeland scale of scenery.

01 / The ascent

Elevation profile

Start 101 m · Summit 226 m

Gradient by distance1.21 km / 125 m gain

0 km0.2 km0.5 km0.7 km1 km1.2 km

02 / The numbers

Climb statistics

Distance: 1.21 km
Elevation gain: 125 m
Average gradient: 10.3%
Climb category: 4
Start elevation: 101 m
Summit elevation: 226 m

Current weather

At the climb start

Loading weather…

Weather data: MET Norway

03 / 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

8 min

Power throughout: 225 W
Average speed: 8.7 km/h

Based on the 1.21 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.

04 / On the ground