Hey Scrod, I just put some new omniums and a new chain on. This is first day, and the noise is driving me crazy. I've measured chainline, front is about 41.7mm and rear is 42mm, The chain is 1/8" (Z410sl if that matters ) Now I'm wondering if its the 3/32' cog in the back (It has about 1.5k miles on it) it doesn't look that worn. Or Do I need to break in the chain and chainring?