Yeah... I would doubt very much if anyone had perfectly round rings. I was stating that more or less to see if anyone had something that was stated to be manufactured "perfectly round".

This is why when you're tensioning your chain, you should tension it with the cranks in AT LEAST 4 positions. If I were actually track racing, I would probably try to set it up by doing the math so that the cog's non roundedness and the rings non roundedness would line up in most cases. But that would require a graphing calculator and some paper... oh yeah, and time.

Good thing Im not track racing.