Originally Posted by
AnonymousPython
What is the best way to determine the thread size? For the BB The ID is 33.7mm (1.327in) with OD 40.33mm (1.588in) and looks like it's about 24 threads per inch. Threads clockwise for NDS and I am unable to remove the DS because I don't have a big enough wrench so can't determine right now. There were maybe 4 ball bearings left inside and they measure 0.25in in diameter.
Top Tube OD: 26.25mm (1.103in)
Seat Tube OD: 27.98mm (1.033in)
Down Tube OD: 28.09mm (1.113in)
Let me know if I can do tell you anything else to help!
Those tubing sizes look like metric to me.
Match the cup you have beside a known english or metric cup - side-by-side, between a light and your eye, look at the thread match.
If it's metric, the chances are greater that the DS cup is french/right-hand, but swiss ones are left. When you have an unknown, you just go L-R-L-R... gradually increasing the torque until it moves. If it moves and gets tighter, go the other way.
There may be markings on the cup - rings, knurling, and there is a chart you can goggle that has some of the more common ones. If there are and they don't match anything please post here what you found.