Bottom bracket cup unscrewing itself.

[dyna-ti]

Anybody know the reasons that a drive side cup would want to unscrew itself ?

Thats twice its happened,despite me putting fair amount of torque the 2nd time.
No cracks i can see :? everything screwed in normally.

 

[gibbleking]

plumbers tape should sort it ...

 

[8690q]

Bearings binding ?

Not enough threads engaging ?

B\B threads worn. B\B frame threads worn ? Not stripped though.

Just a couple of thoughts.

 

[MarinManiac]

I thought that the cup is supposed to be screwed in the non-chainset side, or the 'pedal-arm' side so to speak.

 

[REKIBorter]

I've had BB cups seperate from the drive side before. Finishline assembly anti sieze lubricant is like copper slip but much much thicker and works well to prevent BB coming undone.

 

[8690q]

I always thought it was strange that B\B's loosened clockwise the same way you pedal.

Imagine how tight they would be to remove if it was the other way around and you had dyna-ti's problem.

 

[dyna-ti]

Thing about anti seize is its just the problem,in fact i'd rather it seized

Im using Ti anti-seize already,the last time it undid i replaced the Ti-AS with threadlock,but it still undoes :?
Think ill nail it in place

 

[gibbleking]

its the frame cup..it must be warped for the cup to keep loosening

 

[dyna-ti]

its the frame cup..it must be warped for the cup to keep loosening

I like your idea about plumbers tape,ill try that if all else fails


Warped how :? i didnt think such a thing could become twisted

 

[cyfa2809]

yeah and i wouldve thought if it was warped that it would be harder to screw in and the warped shape would hold it in better (if you could get it in)
unless its warped radially and possibly unformly :?