Fastest Skateboard Wheels, Bearings, and Bearing Spacers

Ignoring his love for Oust bearings (they are great, though), this does a good job explaining about bearing spacers: [VIDEO]

Snug is all you need. Wrenching it down as hard as it will go is but a bit too much. There should be free rotation with no lateral play to the wheel on the axle. It’s not uncommon for wheels and spacer sizes to be out of sync. Blame poor manufacturing. [VIDEO]

Speed rings are the little washers. Spacers are the tube shaped things that go in between your bearings. Here's a video that explains everything. [VIDEO]

The part you quoted was only talking about Swiss bearings, which is marketing. This guy knows what he's talking about: [VIDEO] [VIDEO]

Here is a video [VIDEO] with pictures that explain how they are supposed to work and how they often times don't work.

Also check out this video. He tells you so much technical things about why a spacer is a good idea. [VIDEO]

It goes in your bearings so you can keep the wheels tight without sacrificing movement speed. However they can have some issues related to proper sizing. See here [VIDEO] They aren't needed and not all completes have them either.

Wheels and bearings aren't always going to match up. There might be something going on with the manufacturing. Check this out [VIDEO]. It should give you some help