Prenteg: Cycling Climb

The climb

About Prenteg

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Simon Warren’s Another 100 Greatest Cycling Climbs

The lane out of Prenteg turns away from the Tremadog–Beddgelert road and climbs sharply through the village. Bends arrive early, with trees enclosing much of the lower ascent and little sense of a gradual introduction. The recorded climb is only 1.45 kilometres long, yet gains roughly 160 metres. Its lower slopes account for a large share of that rise, making the start the place where the climb establishes its character.

The road continues upward beyond the first turns, with the effort staying substantial through the middle. As the surroundings open out, the gradient begins to soften, though the easing comes gradually rather than as an immediate release. The final portion is appreciably kinder than the opening. This description covers the short recorded ascent, before the longer lane's later changes of height. Prenteg earns its place through the contrast between a forceful, enclosed start and a more forgiving upper road.

01 / The ascent

Elevation profile

Start 21 m · Summit 184 m

Gradient by distance1.45 km / 164 m gain

0 km0.3 km0.6 km0.9 km1.2 km1.5 km

02 / The numbers

Climb statistics

Distance: 1.45 km
Elevation gain: 164 m
Average gradient: 11.3%
Climb category: 3
Start elevation: 21 m
Summit elevation: 184 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

11 min

Power throughout: 225 W
Average speed: 8.1 km/h

Based on the 1.45 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