Originally Posted by tatfiend

Sachs made a similar 5 speed hub with a similar looking dual cable shifter which is still shown as available in the SRAM hubs parts list. No real idea of the internal mechanism involved but I have read that the SA ones were not the most reliable shifter they ever made. In fact by reputation the shifters were the item most likely to give trouble on the dual cable 5 speed hubs. There is apparently a reason why dual cable SA 5 speed hub users seem to recommend the use of a 3 speed SA shifter for the right cable and a friction derailleur shifter for the left cable.

Almost certainly reasons why both SA and SRAM current 5 speed hubs have been redesigned to use a single cable shifting arrangement. The dual cable hubs when shifted with two shifters require a very odd and non intuitive shifting sequence. The only hubs currently using dual cable shifting are the NuVinci and Rohloff hubs and on those it is a dual cable pull-pull setup for shifting up and down, in no way similar to the dual cable shifting of older Sachs and SA 5 speed hubs.