The Praxis BB uses a sleeve over bearings, the NDS is pressed in with a headset or bearing press. The DS threads in to the shell which is part of the fixed NDS cup with terminates in a collet which expands as the DS is fitted. The KCNC threads together, but no expansion (which is the purpose of the collet) occurs to further secure the BB.
But BOTH cups of the KCNC are toleranced such that they are a snug sliding fit into the BB30 bore, aren't they ?
Is the KCNC O-ring visible after installation ?
With the Praxis units I've fitted, the o-ring / gasket did not compress further.
Best way to see all this is simply visit the praxis site and watch the install video.
I did, but the resolution/magnification is not high enough to actually see the final state of the O-ring.
When the Praxis cup is pressed in until the O-ring "just barely" contacts the shell, is that intended to compress the O-ring slightly for sealing ?
About what is the thickness of the O-ring and what percentage is it compressed ?
Sorry to be a pest, I am trying to invision exactly how both these BB adapters work and end up looking without having to buy both.