Yes, new post because this is an entire topic change. (Still super-low Q but this is the mechanics.)
My Dura-Ace Triple FD doesn't go in far enough to shift onto the inner 24 tooth chainring now that I have moved that chainring inboard as far is it will go. Plenty of clearance on the inside in low gear once the chain is there, but I cannot get it to shift there. With the old SunTours, I used to take out the bushing on the screw at the bottom of the cage and replace it with a shorter stack of small washers. Well the D-A doesn't have the screw. The cage is bent into a wide "J" around the chain. So I had the thought "what if I added metal to the inside of the outer cage plate to push the chain off the middle ring?" Wrapped the outer ring with aluminum sheet metal. Shifted! Nicely. But self destructed as I knew it would after the chain quickly wore though the aluminum, then ripped it off. Still, point taken. Now, how to do it in steel? Well I made a piece that fits inside from the bottom of the "J" to just below where the chain sits in the highest gear. Taped it in place with packing tape and went for the ride in the post above. Wow! A joy. (But not for the world of index. On the middle and small chainrings, FD adjustment has to happen every few shifts in back. NBD for us DT folk.)
Next challenge - that packing tape is not the permanent solution. Will 3M Extreme double sided tape work? Picked some up and am going to try it. If that doesn't, I could drill two holes in the cage and drill and tap the steel piece. (For now I am using Home Depot 1/8' flat bar. On hand and easy to work.)
Does anybody know of a FD that works for triple, fits a 34 mm seat tube and travels far inboard? (Narrow cage or the ability to narrow it would be nice, both for quicker shifting and because the crank is pretty far inboard on this bike. (The whole point - Q-factor.)
That piece of flat bar just got taped in with the Extreme. Shifts really well. The chain does hang up on the flat bar when I shift to the middle from the outer until I bring the FD back out. With it hung up, there is no push to get it onto the inner ring. Probably if I file off the "shoulder" on the top, forward-most part of the flat bar where the chain hangs up, it will behave and fall off. (It does seem to run just fine while "hung up", just quite noisy.)
Another adventure into the unknown corners of "out of spec".
Ben