Britain's Baby Zoncolan? How we found maybe the steepest cycling climb in the country

Deep in the dark heart of Wales, climbing nut Simon Warren thinks he has discovered Britain’s steepest hill. This is the story of how he found it and just how painful it is to ride

Abdon Ddu
(Image credit: Andy Jones)

“There’s always a bigger fish.” That’s what the ancient proverb says, and just when I thought I’d ridden the steepest road in Britain, and put the matter of determining the country's toughest cycling climb to bed once and for all, up popped another hideous incline to further move the goalposts and redefine suffering.

When I first tackled Hardknott Pass in the Lake District I assumed nothing could ever beat that, but then a few years after I discovered the road up to Abdon Burf in the Shropshire Hills and my perception of torture was changed. A while later the utterly horrendous Cowlyd in north Wales found its way onto my radar and again the slate was wiped clean and a new standard was set.

For a while there I thought I’d settled it. I’d evaluated the merits of all contenders from Yorkshire's Rosedale Chimney to Ffordd Penllech via Bushcombe Lane and Vale Street but then came that bigger fish, then came a new vision of hell: Afon Ddu, AKA the Baby Zoncolan.

This mini monster was brought to my attention by hill climb master and double National Champion Dan Evans after I noticed a string of expletives in his Strava feed. If a man with legs as strong as Dan’s struggles up a climb then what chance do us mortals have? I asked. I had to go and check it out.

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A few weeks later I arrive with our photographer Andy, Dan and his wife Jess - a hill climb champion in her own right - to share the experience with them and get the local low down on this insane 700 metres of vertical concrete.

Abdon Ddu

It only gets harder! 

(Image credit: Andy Jones)

Avoid it like the plague

The ‘road’ if you can call it that was built so vehicles could access the giant pipelines that draw water from Llyn Cowlyd and Llyn Eigiau to feed the Dolgarrog hydroelectric power Station and the water treatment plant that sits on its slopes. Named after the river beside it, the Afon Ddu (Welsh for black river) which flows down from Llyn Cowlyd I ask Dan how he first came across it.

“Most local riders know it’s here, we gave it the nickname the Baby Zoncolan but we all avoid it like the plague. The first time I went up was on a mountain bike and even that proved almost impossible, however, once I got to the top I knew I had to return on a road bike to see how fast I could ride it,” he recalls.

Afon Ddu starts abruptly from the main road and you’ll need just one gear, the lowest you can fit on your bike. Riding alongside Dan with Jess tucked in behind we set off, all three of us understandably apprehensive of what lies ahead. Dan is his normal chatty self as we hit the first ramp, our wheels getting their first taste of the ribbed and abrasive concrete surface that would do its best to hinder our progress the entire way up.

Bending right the slope immediately kicks up to around 25 per cent but this is mere child’s play compared to what lies ahead. After around 50 metres the second bend arrives where on the corner there is a slight leveling, Dan immediately heads to the shallower part of the corner here to catch a few seconds respite. “You have to take each and every opportunity to recover when it is presented, no matter how slight” he says. With this in mind, I put my eyes to work scanning the gradients ahead looking for any stretch of reprieve, no matter how short, where I can take a break from the infernal torment.

From bend two the road swings left, kicks up then eases back to rumble across a cattle grid and so far, so pretty ordinary but then, up ahead the road arcs away to the right and here it begins to look serious. As I force round this wicked right-hander, bend three, the pale, rugged and debris-strewn surface rises up like a wall through the trees.

Dan is still chatting away but I’ve fallen silent - there is no space to fit words in-between breaths. “It’s quite a strange effort needed to try and get the KOM,” he explains. “Even though it’s very short you have to go so slowly at first. It’s so incredibly steep that even 10 seconds of going too hard early on and you’ll blow it, you really have to measure it just right.”

Abdon Ddu

Dan Jones's climbing prowess and local knowledge showing on the steeper sections of Abdon Ddu

(Image credit: Andy Jones)

We’ve been crawling skyward for about two minutes, covering just 250m of tarmac as we round bend three. Between bend three and four the pitch increases to a brutal 30 per cent then backs off slightly so we can recover for an instant before it kicks up again. Straining to reach each successive crest burns more matches then to further compound the difficulty the act of zig zagging, (the practice where the cyclist tries to marginally reduce the severity of the slope by riding left to right) is rendered impossible by the unbroken line of slippery debris that runs along the road’s centre. I’m now trapped on a two foot wide strip of rippled 30 per cent concrete fighting for survival. The Floor is Lava is nothing compared to this road.

At the end of this long stretch, as we reach bend four of four. Here there is another leveling, a plateau of sorts before things turn from nasty to insane.

Dan tells me he brought none other than Andrew Feather (current national hill climb champion) here a few weeks back. “He was in north Wales pinching some of my best KOM’s so I thought he deserved some punishment. I did warn him how bad it was but he was like, yeah, it’s just another hill. When we reached this last hairpin though his jaw hit the floor,” he recalls.

I can see why. If you’ve ever been to Manhattan and walked the streets straining your neck upwards to admire the skyscrapers, well, for a moment looking up this road it feels like that. Rounding the corner I spot our photographer Andy ahead and see he isn’t in position. “ANDY!” I scream, we are coming. There is no dress rehearsal for this stretch of road, this is one take and one take only.

Abdon Ddu

How steep? Or should we be asking, how accurate? Simon and Dan get to grips with Pythagoras Theorem

(Image credit: Andy Jones)

It’s from here that this road separates itself from its peers, and its from here that everyone will be pushed to their limits. Ahead lies 30 metres that has every single ounce of muscle straining like a weight lifter attempting to raise four times their body weight above their heads. My veins are ready to explode as I push and pull through each agonising revolution of the pedals. I dare not look up and in a situation like this it is best not to concentrate on the finish but just live in the moment, trying to stay on two wheels, preserving forward momentum. My bike is creaking. My knees are ready to snap. My puny cycling arms are shaking like a frightened kitten. But I have to keep fighting.

As Dan waltzes off ahead I am beginning to falter. Holding a straight line is becoming all but impossible and the effort needed is simply unsustainable. But the end of the steep ramp is within touching distance. I can now hear Jess approaching from behind, her 34 x 32 slightly more suited to the venue than my 34 x 28, judging by her colourful language I assume I am in her way. In an attempt to move right, my front wheel lifts, there is a bang, my right foot instinctively unclips and that was it, I am gone. Unceremoniously I hit the floor and proceeded to tumble southwards just missing Jess by millimeters (how she stayed upright I’ll never know and sincerely I apologise for ruining her QOM attempt). Inspecting my bike it appears my right pedal has partially disintegrated. But had this happened before I hit the deck or after? I can’t say for sure but I decide to stick with before to salvage what I can of my fragile ego.

With one and a half pedals and dented pride I manage to make it to the top to join Dan and Jess at the finish outside the water treatment works. I slump over the bars. If any more proof was needed, this road takes no prisoners., it is utterly savage but that’s what we love, right? If someone built it we will damn well try and ride it, even if it means falling on our ass because. I say a big thank you to Dan and Jess for joining me for the morning it’s then that they point out to me, if you thought it was hard on the way up, just wait until you go back down.

This feature originally appeared in the September 23 print edition of Cycling Weekly magazine, on sale in newsagents and supermarkets, priced £3.25. You can also subscribe to the magazine, save on the cover price and get it delivered every Thursday. It's also available via Apple Newsstand and Readly.

Simon Warren
Simon Warren

Simon has been riding for over 30 years and has a long connection with Cycling Weekly, he was once a designer on the magazine and has been a regular contributor for many years. Arguably, though, he is best known as the author of Cycling Climbs series of books. Staring with 100 Greatest Cycling Climbs in 2010, Simon has set out to chronicle and, of course, ride the toughest cycling climbs across the UK and Europe. Since that first book, he's added 11 more, as well Ride Britain which showcases 40 inspirational road cycling routes. Based in Sheffield, Yorkshire, Simon continues to keep riding his bike uphill and guides rides, hosts events and gives talks on climbing hills on bikes!