Originally Posted by
cdejesus24
I know this sounds silly, but if you get a chance, pick up the frame, shake it, and see if you hear the noise. sometimes things like grit or sand get lodged inside the bike's tubes.
+1, often times bikes come straight out of the factory with crap stuck in particularly the seat and chainstays. There are also often holes drilled as a release for welding that can pick up crap.