The Simplex SLJ derailleur with the front control arm has a rather neato trick to it - the cable is routed through the clamp pivot, which is hollow !! This is how they got the derailleur cable from behind the bottom bracket, and up through a cable-stop, without limiting the "reach" of the SLJ derailleur. I have some rather intricate pictures of a Raleigh RRA that show the front derailleur cable housing going through quite a contortion before hittin the clamp-pivot/cable-stop!
Unfortunately, I am told, this makes for a really weak pivot and they eventually break. This is why the follow-on SLJ models used conventional routing, behind the seat tube, through a regular cable-stop.
- Don Gillies
San Diego, CA, USA