1. (00km) Start at the square in Llanwrtyd Wells with your back to the Neuadd Arms Hotel and TURN R towards Abergwesyn. In Abergwesyn 8.3km (5.2m) TURN L and follow the old drovers road over the cattle grid and up the steep sided Abergwesyn valley. The road drops to cross the River Irfon (over what are locally called The Irish Bridges because, when the river is in spate, the water covers the bridges!) and then up the fearsome Devil's Staircase with a gradient of 1:4. Thankfully, climbing stops after about 1km (0.6m), the road levels out before plunging down an equally steep gradient to the next junction.
2. (15.3km / (9.5m) TURN L (signposted RHANDIR-MWYN) and follow this road. Stay on this fairly level road along the side of the valley of the River Towy then around the Llyn Brianne (there are many view points and various picnic sites) reservoir. It becomes more hilly to the south.
Llyn Brianne is a spectacular reservoir at almost 300m (990ft) above sea level. It holds over 64million cubic metres of water contained by a 91m (300ft) stone-built dam and is the largest of its kind in Europe. To visit the dam TURN R after a short descent and a cattle grid at about 29km (18m).
Carry on past Dinas Hill which is an RSPB nature reserve and a good place to spot Red Kites. Stay on this road, keeping L into Rhandir-mwyn 36km (23.4m) then KEEP SO past the pub for about 2km (1.2m) to a T-junction.
3. (38.2km/23.7m) TURN L and follow the steep road towards Llanerchindda. In Llanerchindda you descend a VERY STEEP road with hairpin bends and on down the valley of the Afon Bran, under the spectacular viaduct carrying the Heart of Wales Railway. Just after Cynghordy Hall TURN L 44.5km (27.7m) to join the usually busy A483.
4. (45km/28m) NOTE: you can TURN L and follow the A483 back to Llanwrtyd Wells which is 10km (6.2m). Far better though to finish this epic ride on quiet, undulating roads. TURN R and follow the A483 for about 0.5km (0.3m) and TURN L up the hill all the way to Tirabad 53km (33m). KEEP L in Tirabad and follow this rolling road to Cefn Gorwydd x-roads 58.5km (36.4m) then TURN SHARP L and follow this road back to start.