Some of my DD hub motors have 3 of those thin 0.2mm bearing spacer rings, some have one, some don't have them at all.
Are they used to align the rotor exactly with the stator?
So for example if the distance between inner face of left bearing and inner face of right bearing is 56mm with mounted side cover plates and on the axle where they would sit that distance would be 55.5mm, I need a 0.5mm spacer?
My bearings have seals on both sides.
Should the axle (or spacers) really have contact with the seal?
Here is a picture of the axle I am talking about: