B4358 between Beulah and Newbridge on Wye. You can do the route from either direction from the A470 at Newbridge or off the A483 at Beulah. This is a real swooping bendy road with crests dips and nothing to really catch the rider out. The only problem is that its only 8 miles long.If you can build it into your ride from either Llandovery cafe on to the A483 then hang a left at Beulah or from Crossgates cafe onto the A470 then right at Newbridge.It doesn't even look twisty on a map so it comes as a pleasant surprise. I bet a lot will reach the end turn round and do it again in the the direction. It truly is brilliant.