Really interested in Big Wally's future Shock post. I have a 2017 Roubaix Comp, ridden for about 1000 miles which has developed the same annoying knocking from the headset/stem. I have tried numerous ways to identify and cure the fault: removed the FS, adjusted the headset bearings, tightened the stem first to remove gaps between the spacers, fitted thin fibre washers below the stem to absorb play, re-torqued everything, all to no avail. That rattle persists. My experience would tell me that such noises are indicative of wasted energy and wear which in most mechanical systems leads to failure. My other bikes: all Specialized as it happens, all run smoothly and stealthy quiet. Bikes in this price range should not rattle! It would be reassuring if Specialized identified the problem and engineered a fix. Now that would be great customer service, or am I expecting too much from a global company?