It went on quite normally...a few full rotations and it was snug up against the cog. Aerospoke is going to cover it (I'm sending it off tomorrow). The cog and the lock ring were originally installed really tightly but I do run my chain with a little bit of play (to avoid too much friction) but not so much that it'll jump off during skids. Maybe I'll try a little tighter and check it (the lock ring and cog) every couple of weeks or so. I'm definitely going to be a bit nervous about this happening again. It's not a fun feeling skidding at fairly high speed down hill in heavy traffic feeling your cog slip. What sucks is that I was really starting to get all of that down and I don't need that in the back of my head.