I just took a quick 30+ mile round trip for lunch, ha!, and kept hearing a strange "loose" sound. Something that just had to be vibrating, coming from the rear. I have been hearing it for a little while now, but it started to worry me this time going interstate speeds. Well I got back to work and remember reading a couple times on here about that helmet lock causing noise. I checked it and sure enough, loose. Thanks again folks for helping us newbies out, and letting us know the common noises / gremlins. It made me feel better instantly!