I think the problem has not been a constant. In my experience I had one tear after several times going into the mountains after lifting. My CV boots looked like originals so I think that it was a combo of old boots and stretching them out farther than they had been.

I replaced all mine with the Mechatechs then and have not had a tear since. On the way to Moab one of the clamps came loose and cause my boot to come off the cup but no tear.

I have what equaled out to be about a 2.5 inch lift I think.