I switched the stock unbranded 16t cog on my rush hour pro to an 18t eai cog. While both cogs were off the bike, I compared their thickness. The eai cog was slightly thicker. Now when I ride there is a pretty much constant low noise coming from my drivetrain, not enough to sound harmful or degrading, but enough to make me notice it, knowing a silent setup is ideal. The aluminum frame is really stiff and resonates/amplifies the noise, I suppose it wouldn't be as noticable on a steel frame...anyway, if my eai cog is further outboard than the stock set up was, is there a way to adjust my bottom bracket slightly outboard to compensate? I really don't want to install the eai cog on flipped around. I don't have any calipers and intend to get my chainline measured at a shop soon, but wanted to get some advice here first. Thanks

moving the hub will be easier.
A little noise isn't the end of the world especially with a OS Al frame.

yea I'm used to the noise, it isn't that bad...it's lightly noticable. I'll probably just live with it, and somehow manage to carry on.

how long were you using the 16t cog?
i've found that chains and teeth need some time to get accustomed to each other. they're always noisy at first, especially if there's any combination of new and used.

I rode the 16t for about ~100 miles before switching out. I cleaned and lubed the chain this weekend, which helped.