Originally Posted by
ljsense
What about the parts that are put there for marketing purposes?
Those rings are buried in the dust cap and I have never seen Shimano advertise them. No one knows about them when buying a bike.
They keep grit out of the hub. They come on Deore hubs which are for MTBs.
If one is lost maybe a substitute could be cobbled up out of a greased piece of twine with the ends superglued together?