Was the BB retapped?
Was this bicycle imported from Europe, as opposed to sold in the US?
Was this a custom build or team bike?
Spec's can be different.
There is a "Swiss" named thread(35 x 1G- Same as the French gauche/left), where both sides are threaded with the same tap.
If the threads were damaged, this tapping arrangement may have been a solution.
Generally, BB threads are designed to allow the cups to tighten as you pedal forward.
Hence the need for the lockring on the adjustable cup.
I am not certain if the offset from the face of cup to bearing race is the same on both types of cups,
which would affect the amount of spindle protruding, I would suggest mounting it with the adjustable
cup on the non drive side. That way, if it loosened you could adjust without taking the crankarm off.
As to the spindle, make certain it is in the bb with the logo readable from the saddle- if you could see it.
Dimensions and tolerances are pretty tight, and there are many options available.
rusty
Last edited by 100bikes; 06-26-19 at 03:44 AM.