derailleur cable stops - how are you supposed to use these?

[Paul Jacobs]

The snouted ferrule stops on bikes I've had appeared to be brazed in line with the path of the cable, not the center line of the chain stay. So the angle was actually pretty good for modern cable shifting imho. The stiffness of the housing "macaroni" and smoothness of its arc attached to the rear derailleur seems to make a greater difference I think. I always thought if that braze-on for the snouted ferrules pivoted, that would be a great design.

On the other hand, slotted stops often seem attached in line with the chain stay rather than in line with the cable's route. As such there is often a kink or twist in the cable housing within that first inch after the slotted stop where the housing goes through a kind of compound curve to get around the chain stay and behind the arc around into the rear of the derailleur.

Positioning the cable stops is the sort of thing I spend half a morning and three cups of coffee thinking about. This is a disadvantage of not having built 1000+ frames (when it would be done correctly and unconsciously) but one of the advantages of not building frames for profit. I usually end up with an offset stop which is a compromise which minimises the cable kinks at the bottom bracket and the derailleur end of the chainstay.

[Applesauce]

Positioning the cable stops is the sort of thing I spend half a morning and three cups of coffee thinking about.

I seem to recall from my stint in frame-building shop back in university that the measurement is 4"/100mm from the axle center. This measurement, for me, has always meant that the pre-cut piece of housing meant for the rearmost bit of the cable run is the perfect length. (It's 100mm on my Colnago EPS, and on the steel frame I built back when I worked at that shop. I don't have any other road bikes around to verify. It's 4" on the old Ritchey-built Ritchey MTB I have here in the shop.)

Having said that, derailleur geometry has changed considerably in recent years, and I'm not even sure if most current top-end shifters include pre-cut housing any more. Pre-cut bits of OT-RS900 are definitely shorter than the bits sized for housing stops and derailleur geometries of yore.