New rubber dampeners will easily slide into the recess in the wheel, and the internal metal sleeves will be a very tight fit into the dampeners.
When worn however (around 100k miles), the metal sleeves will noticably wobble inside the dampeners, causing adjacent wear on the big flat/round plate that constrains them all... and create slop in the drive-line.
Hint: It's cheaper to buy a complete low-mileage used rear wheel (for perhaps $30) than to replace the dampeners at $100.
Wow. I am just under 100k and I have to really pry a bit to get my drive flange out, no wiggle anywhere, so no wear at all yet. Agree with above- if yo are asking because there is some play, go ahead and address it now.
Well I pulled the trigger on dampers, rubber grommets for the side panels, some seals and other stuff; now just have to wait for it all to show up. Good thing it is raining here, or I would be pretty miffed about the bike being down for the weekend.