Originally Posted by
Turnin_Wrenches
^ This doesn't make sense to me. When you size a chain for a mechanical groupset in which the rider can shift into "small-small" the RD deals with that just fine. It's a very bad gear combination for sure, but it shouldn't create excess slack in the chain.
Proper chain management for cassette cogs of various tooth counts is why rear derailleur cages come in different lengths.
It will reduce tension though (and therefore increase chain slap and maybe increase risk of losing your chain) because the force exerted by any spring is proportional to its extension and you’ve got 2 springs there both closer to their rest length when in small/small. (Might only be the pulley spring that affects the chain tension as I think about it)