Originally Posted by
jimmuller
I've wondered about this spec oncte or twicte. For a triple, you will always have a much larger ring-derailleur space for the middle-granny shifts. Positioning the FD as close to the big ring as possible isn't going to help much. On the Tommasini I just built the braze-on FD mount won't let me set the cage that close to a compact double's big ring, and it seems to shift just fine anyway.
So about the OP's question, try re-installing just the original big ring. See if its ramps help the middle-big shift. It will give you a clue what to do next.
There are many here more experienced than me, Jim is one. However, You can probably get this to work. It just depends on how comfortable you are at messing with the derailleur.
What I have done in the past, is lower the derailleur down to just above the top ring and then tweek the derailleur with a pair of pliers inward on the front side slightly where the chain makes contact with the middle ring. Usually I can get this to work.
These two cranks aren't that far apart in chainring sizing so the derailleur should work. Also the cranks may not physically sit in the same location (RSX crank chain line may have been closer to the frame) as before so you may need to choke up the shifting wire and readjust the limits on the derailleur. Also is the new crank fully tightened onto the bottom bracket?
I'm not someone who thinks lack of shifting ramps should prevent this from working. It would probably work easier with ramps but it should still work.