Carn an t-Suidhe: Cycling Climb

The climb · United Kingdom

About Carn an t-Suidhe

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Simon Warren’s Cycling Climbs of Scotland

Fort Augustus sits low beside Loch Ness; the B862 towards Whitebridge soon gives a very different view of the country. Carn an t-Suidhe follows that eastward road into the hills, passing Loch Tarff before reaching the higher ground near the Suidhe viewpoint. The ascent extends for 8.3 kilometres, making it a sustained departure from the loch rather than a brief rise out of the village.

The opening gains height more quickly than much of the middle, while small changes in gradient interrupt the overall upward direction. Around 402 metres of accumulated ascent makes those easier moments part of a substantial climb. Woodland below and the more open ground around Loch Tarff change the feel of the ride as the road continues towards its crest. The cycling finish is beside the high road, below the nearby hilltop. It is a long climb with a strong sense of leaving one landscape for another.

01 / The ascent

Elevation profile

Start 19 m · Summit 388 m

Gradient by distance8.28 km / 402 m gain

0 km1.7 km3.3 km5 km6.6 km8.3 km

02 / The crux

Where it gets difficult

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

Steepest 500 m average

11.0%

Where to find it

1.60–2.10 km from start

Net height gained: 55 m
Section length: 500 m

The whole climb8.28 km

0 kmFinish

03 / The numbers

Climb statistics

Distance: 8.28 km
Elevation gain: 402 m
Average gradient: 4.4%
Climb category: 2
Start elevation: 19 m
Summit elevation: 388 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

32 min

Power throughout: 225 W
Average speed: 15.7 km/h

Based on the 8.28 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