I spoke with Alpinestars last night about the fit, and was told that it was okay to have it ride over a jacket. There is no way to zip up the coat with the brace under it, so that is really the only option. Their brace was designed to work with their other bionic gear, as the rigid part of the brace (in the back) is the same size as the area on the back of their bionic pressure suit, and it sits there, on top of the spine protector. It also has removable padding front and back to lower or raise the position, leaving an optimal gap between the helmet and the brace. I would like to hear from actual users of this product. I won't do any testing until later in the month, when I plan to take a street ride to Nova Scotia, and plan to wear the brace for the entire 3000+ miles.