friction shifter/FD question

[AngryScientist]

does one need a triple specific FD to mate with a friction DT shifter and a triple crankset, or will any FD work? if a triple specific FD is needed, what makes it triple specific, range of travel?

rando bike coming together....

[Ken Robb]

The contoured "bumps/ridges" are different shapes when I compare my double
and triple derailers but I don't know if that would preclude using the "wrong" one in a pure friction set-up.

[ColonelJLloyd]

Whether or not a double will work well depends on the chainrings you're using.

http://www.cambriabike.com/images/product/large/shim_ultegra_fd-6600_frt_de.jpg

[cachagua]

The shift where the "triple-specific" derailleur gives you the most help is from the granny to the middle. Only, you don't need much help there; you have plenty of room to shift way out towards the big ring, and the if necessary, ease back on the lever once the chain gets up there. So it looks like only a marginal improvement to me.

I'd try the one I've got before I bought another one.

[Ken Robb]

The shift where the "triple-specific" derailleur gives you the most help is from the granny to the middle. Only, you don't need much help there; you have plenty of room to shift way out towards the big ring, and the if necessary, ease back on the lever once the chain gets up there. So it looks like only a marginal improvement to me.

I'd try the one I've got before I bought another one.

This sounds like what I would do.

[oliver1850]

Cage design specific to the ring sizes will help the shifting. Travel can be an issue, depending on the frame and chainline. I've run into lack of inward travel on at least one bike with just a double. On Campagnolo 10 FDs, the links are longer on the triples to provide more travel. You can give whatever you have lying around a try, but you may end up having to find something else. At that point, might as well get a triple specific.