Coyote!

I just replaced a couple of worn chainrings on my old TREK 930. The new large one [46 tooth; 110 mm] had a little cylindrical stainless part that’s threaded on one end. Sure enough, the old one had one of these too that faced outboard and perpendicular to the flat plane of the chainring. When screwed in and tightened, the exposed cylinder is 6mm in diameter and stands out 7mm.

I want to call this little thing a “boss”, but bosses generally guide another part in the right direction.

All I can think is that it somehow aids the experienced biker to somehow re-mount a chain thrown to the outside.

So what is this thing?

Thanks.