The question I asked was asked because the setup I had which followed the formula Large,large plus 2 rivets didn't allow the chain to work in the large back and large front combination which I occasionally would stumble into without wishing to.I have a medium cage derrailleur in the back and a triple front chainset.and the large cog in the back is 32T.I was told I needed a long cage derailleur by some people and a longer chain by others.After buying a "Deore MTB long cage derrailleur I was told it wouldn't work with my brifters,Finally I bought a new chain,added 2 rivets in length and the large large combination now works well enough that I don't need to worry if I inadverttently enter it.Not too much slack either in the small,small combo!Thanks for everyones input.