Short version - I acquired a merlin road frame from a friend who was too short (it's a 60 cm) and am in the middle of swapping out the DA 8 speed components for SRAM rival/red.

I've never seen a BB like this one though - it was a mavic crank and who knows where this BB came from. The merlin is probably vintage mid-nineties.

There were two lockrings, one on either side, you can see the general orientation from one of the photos. There don't appear to be internal threads (this is where I start saying Uh Oh over and over). There appear to be two little... uh, not sure what they are, on the bottom of the BB shell, but I don't see any sort of place to stick a hex wrench.

Before I start whaling on the BB, thought I'd ask, hope somebody knows.

Bottom of the BB shell


Side view


Side view with the lock ring I removed (one on each side)


No visible threads... what the hey.