The Simplex RD's either had a nut which threaded onto the hanger bolt from the back of the frame dropout or, more often, a bolt which ran through the DO from the inside and engaged female thread in the RD upper pivot. If the "cap" is on the inside of the RD, it is no doubt the nut or bolt I speak of. Remove it, then place it inside the dropout and thread it into the upper pivot of the derailler outside the DO. Simplex RD's mount equally well to Campy or Simplex dropouts. They don't need the stop notch in the Campy DO, because they have a spring-loaded upper pivot, but the notch in a Campy DO doesn't interfere with their operation.
Regards,
Jerry "lots and lots of Simplex derailleurs" Moos Huston, TX
I've recently purchased a Simplex SX 630 rear derailleur. Can anyone tell me anything about it ? Also, one thing about it that appears rather different is the fact that where I'd expect a bolt to be to mount it on the frame's hanger there appears to be a sort of a "cap" with hex key head on it. I haven't tried removing this cap yet but I'm wondering if how this whole thing works - it's not immediately obvious how to mount this derailleur.
Also, while it looks like a decent derailleur it's finish is not the fanciest - where does the SX 630 fit in the Simplex line-up ?
John Price
Denver CO