I just swapped out my cranks (out with the 105, in with the 7800 DA and Q rings) and now have 53/39 where before I was set up with compacts. the cassette is the same. is there a rule of thumb for adding links. I can tell the chain is obviously too short when I go big ring and large sprocket. Plus I'm thinking w/ Q rings I may want an extra link.

thanks, being lazy I know but hoping a savant out there can hook me up. thinking adding a few links will do it.