Swapping compact crankset for triple. Some help with parts selection needed.

[DaveB]

Too true. I found this out the hard way. My chain seemed very slack on the 24T ring so I took a link out. Big mistake. I ended up locking the chain up on the Devils Incline just south of SF. The only way I could get enough slack in the chain to unjam it was by removing a derailer pulley. I had to do all this quite literally in the ditch, there is no shoulder. So live with what seems a slack chain on the granny, the amount of time you spend using it is minimal.

Typically, even if you exceed the rear derailleurs "wrap capacity" by quite a lot, the granny ring will be useful with all but  the smallest two or three cogs.  I have one bike with a 13x29 10-speed cassette and 53/42/26 chainrings for a total of 43 teeth which exceeds my road rear derailleur's capacity of 39 teeth.   I can use it with the 26T chainring in everthing but the 13,14 and 15T cogs with out having the chain go slack. 

This is no problem as there is no need for the granny ring with these small cogs and the same gear range is easily available in the middle ring.