I am new to fixed riding, and have a question about cog slip. I really have read through many threads about cog slip/stripping/etc, so please don't just link me to the search page.
Initially, I had my LBS put on my cog and lockring. This is a Formula hub with whatever generic cog and lockring come normally on a Fuji Track Pro.
I was practicing skidding the other day and seemed to have it down alright on a dusty section of road. So I decided to move onto regular pavement, and I could get some little skids down. Cool. I kept going and after a few skids, I felt an ever-so-slight slip of the cog. At that point, I got off the bike and went for some tools. I took off the lockring and cog, and it looked like the threads were still OK. I guess the cog had just unthreaded itself a little bit.
This time I put the cog back on myself. I cleaned the threads, greased the threads, and rotafixed the cog on there nice and tight. Put the lockring on with a proper lockring tool. Next, I went for some sprints around the block, using only my front brake to slow down. Then, I was able to tighten down the lockring some more.
I figured everything would be cool. So I rode around for a few days, but after skidding around some more, the cog slipped again about 1/16th of a turn. I haven't taken everything off to see what it looks like, but I fear the worst, considering how tightly I had screwed on the cog and lockring.
Luckily the hub is fixed/fixed, so I have a second chance. But this time, I REALLY do not want this cog to slip. Is there anything wrong with the way I installed the cog? Do I need to buy a $$ cog? Is the hub a piece?