i have a suntour reverse fd, the cable housing extends from the bottom bracket cable stop to the fd. i would like to change the fd from a double to a triple and i think i will need a cable stop for the outer housing on the seat down tube. are they available for 1 1/8/dia.?
From your description I assume you mean converting from a "bottom pull" to a "top pull" FD.?
The cable originally goes under the bottom bracket.
You can get triple derailleurs in both bottom pull and top pull and I have seen some advertised as capable of both.
Choose the correct derailleur and you won't need an extra cable stop.
The obvious advantage of a top pull is the cable is out of the way of the crud that accumulates under the BB.
(My MTB has rear brake and both derailleur cables routed along the top tube and then down.)
But see:-
http://harriscyclery.net/product/shimano-double-housing-stop-1-1-8-down-tube-2458.htm
The other thing to think about, if changing from bottom pull to top, is the routing of the cable from shifters - along the top bar and then down to the cable stop?
Ride hard or ride home alone!
Yes i think that harris item will work. 1972 puch, the bare fd cable runs from a stop at the start of the downtube to a stop just before the bb. from there to the fd is a section of housing that turns the corner. a cable stop is built into the fd. another option might be to take the wiz [cutoff] wheel to the current fd and just use the built in cable stop just before the new fd. the top option looks like a good call to.
There are also conversion kits to convert "bottom pull" to "up pull" but since you're getting a new front deraileur just get the correct one. Exception: the conversion pulleys are used on some cyclocross bikes since they use road components that are not available as "up pull".