Originally Posted by
mcjimbosandwich
the shimano document for DA7800 says it could handle only 11-27T. what adjustments did you make to make yours run? i'm thinking of getting PG1090 cassette and i would prefer to use my old DA7800 if possible
no adjustments are necessary (beyond the standard settings of limit screws & b-screw). shimano, like all derailleur manufacturers, quotes a conservative number for derailleur capacity and max cog size. of major manufacturers, i believe shimano's quote is the most conservative.
if you're a bit over the limits, don't worry about it. if you're exciting that "bit", then you might lose the ability to go big-big or small-small (which some argue you shouldn't do anyway).