I just completed this route as day 2 of a weekender trip, day 1 being https://cycle.travel/route/cycle_across_the_beacons as a big loop from Abergavenny, camping overnight near Ammanford. I joined this route at Glyn Neath.
The road from Llwydcoed that climbs steeply Eastwards to join the A465/Head of The Valleys road at Baverstock junction, is closed for major road works. Its well signed at the foot of the hill. Don't ignore this, as I did, and end up pushing your bike through a completely unfinished wasteland/building site made of super sticky clay and mud, praying no road workers were around (luckily it was a sunday!)
On the plus side, the major works on the section of A465 that you are forced onto for a mile towards Methyr, means the hard shoulder is coned off, and speed restricted to 40, I think. Meaning the descent feels a hell of a lot safe, you have a lane to yourself, as long as there are no roadworkers in the lane. There was also a bit of diversion to the Taff trail after crossing the bridge, this was signed and fine.
I had a gear cable snap on me outside of Ystradgynlais (not on this route exactly, but the story is worth telling). I was a long way from home, and weighed up my options. No phone service, no train station nearby, ego and pride prevailing... I managed to limp back to the village where I remember passing an interesting-looking (but closed) cycle shop, J.Evans Cycles (not to be confused with the awful corporate franchise). I thought I'd chance it, so I knocked on the door, and luckily the owner, a gentle eccentric, retired old soul who luckily lived above the shop, answered in his boiler suit, ready to go! He kindly forwent his relaxing Sunday in front of the telly to help me out. He opened his workshop to me, moving 2 of his project cars and lots of heavy kit out the way to make space, sold me some gear cables at 1970s prices, and we fixed it together. It took hours due to the fiddly 105 hydraulic shifters on my bike with internal routing, which admittedly I had not changed cables on before. It was very fiddly and no chance I would have been able to do it road-side. We both learnt a lot, despite John's mutterings about modern tech! John is an absolute legend, he's been there since the 1970s, and I am honored and thankful to have met such a kind and patient man in my time of need.
The descent from Brynmawr all the way to Abergavenny was under-sold, it was absolutely epic, and the best thing a tired cyclist could ask for at the end of a tough, mechanical fault filled 2 days!
In general a good route, if a bit ugly/bleak in parts, but thats south wales right? Worth it for the descent anyway!
