a friend of mine recently purchased a Mark V complete. when she peddles or spins the wheel while is it off the ground, there is a continuous buzzing sound coming from the drive train. all parts are stock and the chain is new and properly lubed. chainring and crank bolts are tight and the pedals are tight and greased. the chainring and cog are clean as well.

the sound is similar to a healthy drivetrain when it's lifted up and spun hard but much louder. the sound seems to be coming from the rear wheel more than anything, although it's difficult to pinpoint exactly where it comes from. I took the chain off and spun the cranks - no sound.

any ideas of what could be causing this sound and how it could be reduced?

tight chain
or
the bicycle in general don't worry so much

I had the exact same complaint as well. it's not that big of a deal. I degreased the chain and then lubed it and i dont hear the noise anymore. so try that

fire....set it on fire

make sure the rear wheel is centered in the dropout

if the bike is brand new then the chain probably just needs to be worn in a bit
dont worry about it

I found that the lube the chain has from the factory attracts alot of dirt. I have the same problem on my mark v. I'm gonna clean the chain and try some dry lube.