hi, just built my surly steamroller today and im hearing a ticking sound followed by a jerk.. it sounds like its coming form the rear hub, and its especially prevalent when pedaling backwards. wheels are velocity deep v with velocity hubs. i tightened the cog and lockring down good so i know its not that. sorry the description is kind of vague but im very much a noob in terms of maitenance. any help is much appreciated.