Noisy Drivetrain
 

I just had my LBS put a new chain on my road bike. The old one had stretched about a 16th of an inch.
they cut down a 9-speed chain to fit my 8-cog bike. When I rode the bike it worked smoother than before; but, the sound of the chain moving through the drivetrain was very different. It sounded much louder and coarser.

I thought something was wrong. But the wrench took it for a ride and said it was OK. Maybe I'm so tunned into my bike, little things seem like a big deal. Is it common for a new chain to change the sound of the drivetrain?

I had a similar issue with a worn chainring, which ran very roughly and noisily when I replaced my worn 8-speed chain with new one, also 8-speed. Replacing the chainring solved the problem.

Also, I BELIEVE a 9-speed chain's inner link faces are closer together than those of an 8-speed chain. If so, this would increase chain-to-cog and possibly chain-to-chainring scraping.

Have ya given the chain a good cleaning? Clean off that gunk they ship it in and lube it with a good lube.

I agree. Clean the chain well - that stuff on it is more to preserve it than to lubricate it.