Originally Posted by
DaveSSS
Rather than using the big/big plus 1 inch method, try the little/little method. Shift to the little ring and smallest or next to smallest cog. The chain should be as long as possible without hanging loose. As long as the lower end of the cage moves forward and creates some tension on the chain, then it's not too long.
+1
With the same small-small combo your max chain length is the same. Unless your derailleur is not capable of handling the 11-28 and whatever chainring difference you have things will be fine.
I size all my chains this way. A longer chain may bounce a bit more when using the small chainring and smaller cogs but it has a lot less friction in the big chainring and bigger cogs.