Res said:i think they are screws and yes if they are still there and fouling on the wheel remove them
that could well be what is the problem
yet again you lovely mentlegen help me out did a quick check today and both back wheels had one screw in the drum which was sitting on one part of the multistud causing it not to be fully flush...
did a quick trip round the block and got up to 100km/h without any problems or vibration