I just got my new moose Barkbusters from the TT store (Thanx Don) and now I have a problem. My AZONIC 7/8" aluminum bars have a wierd I.D. It is much larger than the aluminum expander nut, but smaller than a steel bar. The first couple inches of the bars are opened up by the factory to make the hole larger. But it's an in between size. any ideas on how to shim the expander nut so it is secure. I dont want these things shifting like my old ones did.