Originally Posted by froze
Interesting; how reliable is this procedure? Will it strip out or rotate if one was to tighten the cage bolt too much?
Not in my experience. You do have to tighten down hard to make sure the rivet part is truly snug on the other side of the metal. The usual indicate is slight deformation of the outside "ring" of the Rivnut to conform with the curve on the tube.
I've put on three or four sets of these now, and all have worked well. The best example was a bottle cage on the bottom of the downtube on my Fuji Touring -- everything is still going perfectly after four years, and nary a sign of loosening of the Rivnuts. In another case, I put on rack mounts on the seat stays of a tandem.
My only experience with loosening was on a Merida 900 Extreme that I own. An aluminium frame with a downtube that has a quite tight curve on the top. The Rivnut used on that obviously had trouble finding enough purchase underneath to remain in place. When it loosened off, I used the same trick with the aluminium flat bar and tightened it up again (cautiously).