I can confirm it's a rubbish design, now I've pulled the NDS apart.
Bearing is recessed about 2mm (no idea if this is correct; there's nothing securing it at that depth). There's a spacer, a wavy split washer, a rubber seal and the 'bearing shield.'
What's the point of a spring washer if there's nothing to retain it? What's supposed to hold all that stuff in? How do I know if the bearing is actually seated against the circlip?
And why isn't the BB noisy unless it's under load?
The bearing depth is about right. Its inner depth is limited by a spring clip in a recess in that aluminium sleeve.
The wavy washer simply pre-loads the bearing and crank a little so that any end-fload doesn't go clunk-cluck as space is taken up from left to right.
Don't call that rubber ring a seal. That's an insult to proper bearing seals.
The stuff stays in by itself. It actually does.
The BB is noisy. remove the chain, place the bike in a stand and put your ear somewhere on the top tube. After figuring out that your teeth are far away from the pedals, spin the crank and listen. The bearing will talk to you and tell you to either rrrrrrrrrreplace it or shhhhhhhhhhht, leave me alone. The rumble is accentuated under load. It will only show up in finger-rotation of the spindle if it is really stuffed.
