Loose rear hub nuts/studs

[dickie]

Took my series 3 to work today for its first run out after a lay-up of about 6 months. On the way home the back end felt very wrong so I pulled up and found that two of the four hub studs (the ones with left-hand thread one end and right hand on the other) were no longer there. Rather glad that I checked even though I was only 2 miles from home.

Easy to fix, but is there a known reason for this to happen? I'd assumed that as they are left-hand thread, they would tighten as you ride rather than loosen.

Any advice?