Originally Posted by
SkyDog75
....... Another option is to re-tap the bottom bracket to Italian threading, which has a slightly larger diameter. After tapping to Italian threading, just install any ol' Italian threaded bottom bracket. The small catch to this is that Italian bottom bracket shells are a little wider than English -- 70 mm versus 68 mm -- so you may need to use a thin spacer between the drive side cup and shell.
THANK YOU SKYDOG! You might just have given me a better option for my old 80's vintage Canondale frame. The threads are completely gone other than some stubble. A regular BB slips in with NO thread bite at all. But this could be the cure it needs.
Smurfy, there's another thread right now about using Loctite Form-A-Thread. The use the other member wants to put it to is simply not going to work due to the torque issue.
In your case the lack of support from the worn outer portion will seriously strain the last 1/8 worth of good thread. So it too would tear out pretty soon. BUT! If you were to use the Form-A-Thread goop it would provide the support needed to let the last few threads do their job and stabilize the BB so those last good threads don't see a cyclical load that would tear 'em out at the roots.
The Loctite stuff is basically just epoxy. A GOOD epoxy but still just epoxy. You would get similar good results with something like JBWeld for an application such as this.