It's an old no name bicycle. It's a case of me replacing "old school" (spindle and cups and bearings in cages) pieces with a UN-55 cartridge (or dying in the attempt lol). the old parts were used to determine that UN-55 is the right one, if only a cartridge with fit THROUGH the shell!
As to "what bike is it", Jah only knows and he aint tellin'. LOL, I don't think it has a "group" other than low-end shimano (IIRC, the RD I replaced was an Altus). I've had zero luck trying to find info on Columbia/alum-comp.
I really should look for a hosting site for pics (if that's the way to get pics posted) which would add some clarity to this discussion.
All that said... the "insert" inside the shell is too small diameter to fit the (otherwise correct) UN-55 cartridge through <eye-roll>.
On seeing the phone pics of it, one LBS said "never seen the like before" (figures my little learning project is not only too cheap to be bothering with, it's also a flippin' "one off").
I suppose I could replace like with like, foregoing the cartridge option, but where to find the "equivalent" loose parts?
I'm leery of trying to "twist out" the insert/sleeve due to very real possibility I'd jack up the BB shell threads (which is also the reason I stopped hitting on the insert with a hammer and punch, not to mention it didn't move a single millimeter).
So there's the "update" and I'm off to visit other LBS to see if they are also mystified by my phone pics.
Tatt