Start of Climb - Aberdar, Rhondda Cynon Tafe Province, Wales
This southern Wales climb begins in Aberdar and is extremely steep as we leave the southern edge of town to begin a pleasant 5.3 km climb just south of Brecon Beacons National Park.
Steepest segment of the climb - 500m mark @ 19%.
The first 2.7 kilometers of this climb are at a very challenging 9% gradient. After that, we coast to the finish at a barely discernible 1% grade.
800m of descent beginning at 3.1 km.
A tip from the challenger-seekers of George Oliver Foundation:
“Bryn Du leaves from the village (town?) of Aberdare and is kind of a funny one - you are in a little place with shops and schools and suddenly you are riding up this steep slope. Of course, it being a Welsh climb, it is a 7/10 climb (just like the previous 2 I had done!) and you ride over a cattle grid...
Cattle grid riding on a road bike with skinny tyres is a bit of a leap of faith - you just point the wheels at the grid, perpendicular to the bars and cross your fingers that they won't twist! Generally I think that taking them at speed kind of makes you "skip" across them quicker - 2 problems are that going up hill, speed is rarely an option and the faster you go, the more it will hurt if you fall off!” http://100hillsforgeorge.blogspot.com/2011/04/hill-no-8-96-bryn-du-rhondda-cynon-taff.html
Steepest kilometer begins at km 4.9 (6.6%)