If you look at the picture below you can see the profile of the ring is raised on one side and I had it fitted the other way, closing the gap between the middle ring just enough for the chain to 'miss' the ring when down shifted from middle, I switched this round and tweaked the stop adjustment and its near perfect.
SGX Granny ring showing profile

Previously fitted.....wrong !!

Got a good result on eBay recently, a pair of NOS M-650 DX hubs, complete with Quick Release skewers for £15
Mmmmmm.....NOS hubs
