Drive-side cup keeps coming loose....Any idea's folks ?

[Little Al]

Drive sid cup keeps coming loose

Check that the bottom bracket shell is square on to the cup & flat, easiest way i `ve found is to wind cup nearly all the way in, & check the gap with feeler gauges. if it`s not the above[square& flat]it will only tighten on a small part & will work loose as only part is tight. If its way out most LBS`s have a bracket facing tool Are both threads right hand [as Italian]as these seem to suffer more problems than the Left Right combo`s . Another fix is to use the thinnest Sturmey Archer sprocket spacer betwwn bracket & cup [but this will alter the chain line slightly

 

[bm0p700f]

Thgread lock should work wothout tioghtening up very hard.

Modern Campy BB's for example are menat to be threadlocked and only hand tight. Do it too tight and it might never come out again withou serious swearing aand grunting.

 

[keithglos]

Apart from the right hand thread, the main problem is that riding it loose has stretched the bottom brcket shell, as you pedal the cup works its way round like an epicyclic gear.
Just do what is suggested, and hope it works.