Originally Posted by sivat
I just put a soma cog on my bike when i switched to a 1/8th drivetrain and its terrible. It has a weird tooth profile that catches the chain and causes all sorts of bad noises and rough spots in the crank rotation. I switched it out for an EAI and it's nice and smooth now. I'll never touch the somas again.
Just out of curiosity, was the chain and soma cog new. What you are describing sounds like a new chain on a worn cog.