Ok I can't figure this out. Am I using the wrong chains? I don't know. Got this 2011 Masi Partenza. Came with the typical FSA Tempo cranks but with steel rings. Found some aluminums of the same tooth count and bolted them up. A tiny bit of rub at one portion of the rings (they're still really straight though) so I threw in a set of .6 spacers to see how that would work. Works perfect but now when downshifting the chain gets stuck in between because of the bigger space now. (obviously) Now I know this all easy obvious stuff but what confuses me is that what was the old steel rings doing that these arent? How did the steel rings find a way to not rub and still have the correct space to not suck the chain into? How did that happen?

My Schwinn Tempo's doing the same thing. Never had this problem on all my other bikes before. This is why I'm confused.