You need a lockring. hard to tell from that top pic but if thats a fixed hub it should have an extra bit of thread to screw on a lockring to secure the sprocket.
Anymore close pics of the hub?
@motman started
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You need a lockring.
hard to tell from that top pic but if thats a fixed hub it should have an extra bit of thread to screw on a lockring to secure the sprocket.
Anymore close pics of the hub?