I'm having difficulty getting a new BB to thread into a new frame. The drive side cup goes in fine, but the non drive won't engage properly. The cups are clearly marked right and left, and the direction in which they should be tightened. Just to check the threads weren't damaged on the BB cup I ran a screwdriver along the threads and it seemed to go the wrong way - i.e. when I was following the tighten direction the screwdriver came off the end of the threads. On a whim I tried the cup in the drive side of the BB shell and it went it fine when turning in the opposite direction to the arrow (but the correct direction for tightening a DS cup - towards the rear wheel). Now my brain is fried and I can't work out should this be possible or not i.e. should a left cup be able to thread into the drive side (right) BB shell?
Trying to work out if the BB shell needs chasing, or if the BB cup has been threaded wrong.
Thanks
From your description I’d say you have two drive side cups. One has been printed incorrectly with the direction arrows.
Italian threads?
Could be Italian, but you’ll only really find them on road frames - is the BB shell 70mm wide?
Its a T47 BB, BB shell is 73mm.
Forget the printed arrows. Are the two cups otherwise identical? If so, one of them is incorrectly marked up.
Well the threaded part is, the threads all run the same way.
Bit of a pita, luckily I didn't try harder and trash the frame.
