Dyfi Forest: Cycling Climb

The climb · United Kingdom

About Dyfi Forest

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Simon Warren’s Another 100 Greatest Cycling Climbs

East of Aberllefenni, the mountain lane towards Aberangell climbs into the wooded hills of Dyfi Forest. This is the western approach on that connecting road, with the recorded ascent ending on the high ground before the descent towards Aberangell. The forest's steep hills and plantations give the ride a close, layered setting. Across five kilometres, the road gains about 220 metres, with changes of gradient that prevent the ascent from becoming one uniform pull.

Early climbing gives way to a less demanding middle section, including a small interruption in the rise. That pause does not signal the finish: the road gathers height more insistently again, and the last part carries the strongest sustained climbing. The resulting effort builds late, rather than being decided by the first slopes out of the valley. Dyfi rewards attention to the road's changing shape, with a final climb that feels more substantial than the overall figures suggest.

01 / The ascent

Elevation profile

Start 115 m · Summit 330 m

Gradient by distance4.97 km / 221 m gain

0 km1 km2 km3 km4 km5.0 km

02 / The crux

Where it gets difficult

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

Steepest 500 m average

8.9%

Where to find it

3.70–4.20 km from start

Net height gained: 44 m
Section length: 500 m

The whole climb4.97 km

0 kmFinish

03 / The numbers

Climb statistics

Distance: 4.97 km
Elevation gain: 221 m
Average gradient: 4.3%
Climb category: 3
Start elevation: 115 m
Summit elevation: 330 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

18 min

Power throughout: 225 W
Average speed: 16.7 km/h

Based on the 4.97 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