I am building a NOS 2010 Eddy Merckx EMX-5 frameset with 11 speed Chorus. The rear brake cable runs through the top tube. It sounds(and feels) like the cable is rubbing against something about a third of the length from the head tube. It is not preventing the calipers from opening when I release the lever. And I am in my basement with low ambient noise and CF tubes really seem to magnify sounds. Could the inside of the tube be unfinished enough that there is extra CF and it rubbing against that? Is this a problem? Ideas? Solutions? Thanks.