ive a nice road bike but purchased it in a not great bike shop, so god knows which monkey put it together. My rear derailleur seems to touch the rear cogs in the two biggest cogs on the rear. ive adjusted the screw to make them not touch but it screwed the whole way down before it stopped touching and now it clacks a lil bit when i crank on the pedal. its a 20 dura ace. i shouldnt have any issues. im thinking maybe the chain is slightly to short
what u guys think?