Cut from Cadillac Serviceman 1958 where the following 2 tips one in May edition and the following in Aug edition regarding how to eliminate the annoying rattle and clicking that often can be heard from the original hubcaps .

My own experience is that these 2 tips is hard get right and I finally taped a narrow piece of ductape on the rim where the hubcap contact points are and then finally got rid of this annoying clicking. Good Luck !