Cycling the Stwlan Dam Climb

Stwlan Dam

I’ve wanted to ride up to Stwlan Dam climb ever since seeing it in Cyclist magazine a few years ago. But always seemed to stay too far away from it to ride up. Staying further south in Porthmadog for a change, I had to make the most of the chance to finally tick this climb off the list.

I’ve written about riding in North Wales before here, but the weather this weekend reduced us to just short blasts around points of interest such as Stwlan Dam.

Stwlan Dam

The Stwlan Dam climb is on a road closed to cars. We lifted our bikes over the gate and then went through the kissing-gate. The road is used by the odd car from the electricity company but that is the only traffic you will meet. This road leads up to the dam way up in the hills above the village of Tanygrisiau. The dam feeds water from the lake at the top down to the lake by the village which runs a power station. You can just about see the foreboding dam arches from the main road if you’re at the right angle but can be surprisingly well hidden.

Stwlan Dam Hairpins
Some of the many hairpins

We started the Stwlan Dam climb on a rise which ended up lasting half a mile and averaging 9%. I set off quickly but ended up settling into a rhythm. It’s a touch longer than you first think! At the first little zig-zag, I looked back and my ride partner was still in sight below. As I rounded the next corner, I wouldn’t see her again for a while. This corner gave me the first proper sight of the dam itself. The tall dark arches gave it an imposing feel, almost like something Lord of the Rings-esque.

Stwlan Dam Lake
The only way to see the lake is to climb up here

The next section was the reason that it had caught my attention in the first place. A very old copy of Cyclist magazine contained the climb and made it look beautiful. 8 hairpin bends are at the top of the climb leading to the dam. It’s rare to come across so many hairpins on a climb in this country and it gives the climb its distinctive look.

The first hairpin up to Stwlan Dam was steep but the middle ones eased off to a now much more manageable 7-8%. The final stretch, including the last hairpin, shot up to 14% just to make things difficult. The view of the lake at the top made the effort worth it. There’s a topograph up a short set of stairs to point out local landmarks. It’s handy to point out the local landmarks and hills in the area. Obviously, you might miss out on a cloudy day!

You’ll also see the lake that the dam has created – Llyn Stwlan. It’s quite well hidden as you can’t see it from the main road below and you’d have to be walking up the nearby overlooking hills to see it from another angle. You can’t get particularly close to Llyn Stwlan though as the main road across the top is often blocked by a gate.

There are a couple of other climbs up to dams in Wales – Marchlyn Mawr is the most obvious one. Ffynnon Llugwy is another and an absolute brute! And if you fancy climbing some of the other top Welsh climbs, I’ve prepared a list of 7 of the best. Stwlan Dam is definitely a climb to have a go at and tick off your cycling bucket list.

Can you drive to Stwlan Dam?

Pretty much! There is some Stwlan Dam parking right at the base of the climb in the village of Tanygrisiau. It’s a nice spot with the Ffestiniog railway trains pootling past and the shores of the Tanygrisiau reservoir almost up to the car park itself. The car park is maybe just 400 metres from the bottom of the climb and there’s a small amount of ascent to get you started too. The Lakeside Cafe provides some sensibly priced food and coffee, probably best to save a visit until after you’ve done the Stwlan Dam climb though!

Stwlan Dam Strava details

The Official Wales Climbs version of the Stwlan Dam Strava segment can be found here.


Subscribe to receive posts from