Originally Posted by pwdeegan

good questions; let me clarify.
1) the chainring is already on the outside (and currently with a chainline at 45mm); it's a Sugino single, and i like it and intend to keep it.
2) no; Rohloff internals are off-limits to me and other commoners; only access for Rohloff experts, and maybe wrist-watch repair people. Three internal planetary gears, many little little internal parts; things that when generally left untouched (save for oil renewal) never go bad. ain't broke? don't fix.
3) it's for a Rohloff hub drivetrain. but apparently, many a MTB triple outside-most chainring also runs at 54mm (not necessarily that the corresponding BB must meet that length), according to Rohloff, Sheldon, Thorn, et al.

I guess it's not a big deal then, to have a 123mm BB. I'm just so used to my 1x9 and its relatively close-in chainline that it seemed big. i might just get a 120 and use up 2-3mm of PW BB cup flex. as it stands now, my BB cups are asym. by ~1mm anyway, and it rides fine. Anyway, glad to have had my sleepy-head math 2x checked. Thanks all!