Rhiwr Road: Cycling Climb

The climb

About Rhiwr Road

Collections

Simon Warren’s Another 100 Greatest Cycling Climbs

From the bridge by Clydach Ironworks, Station Road begins the ascent out of Clydach Gorge before the route continues onto Rhiwr Road towards Waunllapria. Buildings and trees keep much of the road enclosed, so the surrounding height is felt through the climbing rather than a continuous panorama. The selected ascent gains roughly 200 metres in 1.7 kilometres. There is little easy ground at the start, and the lower road soon becomes more demanding still.

The central portion maintains that steep climbing, with the effort concentrated well before the finish. Higher up, the gradient finally begins to soften; the last stretch is distinctly kinder than the road below. That change matters after such a sustained lower bank, allowing the ascent to end with something more measured than its opening. Rhiwr Road has the character of a lane working directly out of a deep valley: enclosed, forceful and relieved only towards the top.

01 / The ascent

Elevation profile

Start 157 m · Summit 361 m

Gradient by distance1.67 km / 204 m gain

0 km0.3 km0.7 km1 km1.3 km1.7 km

02 / The numbers

Climb statistics

Distance: 1.67 km
Elevation gain: 204 m
Average gradient: 12.3%
Climb category: 3
Start elevation: 157 m
Summit elevation: 361 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

13 min

Power throughout: 225 W
Average speed: 7.5 km/h

Based on the 1.67 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