Sorry to bring this thread back from a few months ago, but I have a new wheel on my bike and some track cogs lying around as well as the old wheel. I thought I might try putting the track cog on the wheel and running around town on it before I decide to drop the money on a real fixed wheel. I have both brakes since it's a SS, so that's not much of a concern. The problem I have is that when I try to thread the cog onto the wheel, it just stops and won't thread on ANY more than maybe 3/4 of a turn. I'm not sure why it doesn't want to go on, are the threads different? Am I just not using enough force to get it on?