I just purchased a set of aftermarket wheels for my 95 A6 that were off a 96 A4. When I did a test mounting, I noticed that the hub is a smaller diameter than the opening in the center of the wheel. This means that the wheel is held on only by the five lug bolts, and is not supported or located by the hub. Is this okay, or do I need to get some sort of spacer or insert? Thanks Jeff 95 A6Q