In a message dated 17/03/2008 1:56:23 P.M. Central Standard Time,
LISTSERV@GERRY.VANAGON.COM writes:

I know  of 3 in my close circle that have broken over the years. I have
heard of  several others on this list that broke. What is the meaning of
'prone'?  While it isn't common it also isn't exactly rare.

Incidentally all 3 in  my circle were in 86 models. All broke at the
point where the setscrew  creates a weakness. All were in the 150k mile
and over  range.