I just started to service the bearings on my Carrera Subway 1. I removed the cone and found that the outside ring separates from the main cone. You can see this in the pictures.
What is this ring? And can they be purchased?
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Sign up to join this communityThe outside ring is a bearing seal. Looking at your picture, it may be damaged. You can try to bend it back to its original shape.
As for can these be purchased: anything can be purchased if you find a seller. But it's unfortunately not easy to find sellers for cones and bearing seals of an unknown hub. Maybe if you try to see if you can identify the hub, what is the manufacturer, is there a model number, it may be possible.
If it's a no-name hub, most likely you will not find parts. But at least for Shimano it may be worth trying to find compatible parts.
However, the easiest way would be to bend the seal back to its proper shape and assemble the hub with the parts you already have. Your cone looks quite dirty, be sure to clean everything, remove all dirt and put fresh grease in. You may want to consider putting fresh set of bearing balls too, they cost next to nothing and are easy to source unlike cones which are hard to source since there are so many shapes.
However, it also may be possible the cone bearing surfaces are too damaged due to dirty grease inside the hub.
Its a "dust shield" and is not directly part of the bearing - you can ride without it perfectly well.
Personally I'd try to keep it - the shield does protect the bearing balls and race from external debris
The shield is not load-bearing so you can simply friction-fit it back in place, perhaps with some gentle persuasion from a socket and hammer. Some 2 part epoxy should hold the shield in place too, but its likely too thick to solder