The lockring and left side "adjuster" have been coming loose on my DA BB. What could be causing that? And what is the fix?
The lockring screws directly on to the adjuster and prevents the bearing from getting any tighter, but doesn't prevent "unscrewing". These are both right hand threaded so I can't think of any unscrewing type forces at work here at all (save the occasional backwards pedaling). Vibration alone doesn't seem like it would make this happen.
This has happened twice in the 800 miles or so since I've put it on. At first I thought it was just the lockring, but I tightened the adjuster almost 2 full turns yesterday. It's possible I never had the adjuster screwed in all the way originally and over the last few months the bearings loosened up enough to tighten it down some more. I used the brochure's technique of "tightening until resistance shows a marked increase and then backing off" and I greased all the appropriate parts. Seemed to work fine and the crank felt smooth, but it felt smooth with no play even when the adjuster was loose so I'm not sure. There are about three threads on the adjuster showing past the lockring after I tightened it, does that sound right?
Yes I'm sure I got the right size BB and I'll get an Ultegra BB next time.