Originally Posted by rpenmanparker

Actually not really when the derailleur arm is pulled full forward as it should be for the large-large combination. And as was said, that is the shortest possible chain. But there are other methods. You can run the chain through the derailleur and over the large front and smallest rear. The right length is when the line between the two pulley axles is perpendicular to the ground in that combination with no extra links added. I have always used this method as it used to be the preferred method recommended by Shimano. Works for me.