Hi. In need of some advice with regards to these. My Audi A4 Cabriolet has a set of replica RS6 18inch wheels fitted. The wheels have never located on the hub since I purchased them and they were not supplied with Spigot rings. I have been advised that these are needed and the absense of them will more than likely be the cause of vibration over 60mph. Contacted the wheel supplier regards to supply of these, less than helpful attitude and they tell me that even with the supply of the part number on the invoice I would need to measure the centre bore of the wheel myself to determine the size. I guess its a question of me finding out if anyone can suggest the common size spigot ring that I am likely to need?