Originally Posted by
KCT1986
If your plan is to only use the larger cogs in the rear with the granny, then with proper chain length, it should work. Shifting to smaller cogs with the granny will cause chain slack but that's not a serious problem, big/big is where the major problems happen.
Actually chain wrap on a correctly sized chain only effects the small-small. Maybe the 1st and 2nd position depending on how far over capacity someone goes.
On the large large the wrap is “closer” to zero, depending on the extension of the cage, since the chain is “almost” going straight from the cog to the chainring.
On the small-small the derailleur cage folds back on the derailleur until the chain sags.
John