Originally Posted by
engstrom
OK, so I ended up having to turn the barrel of the cable about 3/4 of a turn to tighten the cable and make the shift from small to large work perfectly - much more than it seems I should have had to. But the good news is it shifts from big to small and small to big. Then I shifted the rear into the small ring and all hell broke loose. The chain rubbed on the front derailleur on the small chain ring and came off the outside of the big ring when shifted to the big. Isn't adjust the derailleur fun? Oh well, loosen up the cable and try again.
This is one of the very few instances where you need to mess with the limit screws. Specifically, the outer limit screw (the inner one is fine). The outer limit screw is allowing the derailer to move too far outboard and derailing the chain to the next higher gear. Since you don't have a next higher gear, it's jumping off. Screw the tension screw in a little (a quarter turn should be too much).
The fact that it is rubbing on the small ring says to me that the cable is just a little tight. Back off on the tension of the cable a little too so that it will drop down onto the small ring properly.