My rear gears have been skipping from easier gear to harder gear recently, i read someplace else that a way to fix this was to loosen the barrel adjuster a quarter turn by turning it clockwise when standing at the rear of the bike. But where are they? Does my bike not have them installed? if this is the case can I go to my LBS and have them sell me one that is not a campagnolo museum piece? and where should it be installed?