No 'center sleeves" is/are the sleeve between the bearings inner races, just along the axle, that set up the dimension that the bearings sit at WRT each other. It's this sleeve that keeps the bearings from being compressed by the QR/axle bolts tightening.

I see that Phil now uses the reference of "cups" to describe what they use to call rings. So I now stand corrected. As they make this stuff they can call these things whatever they wish to, whenever they decide to. But BITD we all called then rings as there's no real cup like features to them and Phil called them that back then.

At one time Phil had a minimum number of cup/ring threads that they wanted to be engaged in the shell's threads. I forget what that number was but one general mechanical standard is at least 5 threads of overlap for minimal retaining strength. But that's not using any thread locking compounds. Phil's instructions (see the link I posted before) claim a 5mm range of side to side positional adjustment. So measure the amount of cup/ring extending out of the shell and if there's more then a 2.5mm difference between the two sides then either a side isn't fully seated against it's bearing or the side to side adjustment is off of recommended spec. Of course all this assumes a 68mm shell and not a 68.XXX or 67.XXX (or 70 or 73....). Andy