I think one of my kids may know what a hub cap is. I had to explain it to her after she listened to T-Rex. She wanted to know what a "hub cap diamond star halo" was. Unfortunately, I was not able to explain its connection to diamonds, stars or halos, because that would have involved a lengthier discussion of prevalence of psychodelics in the early 1970s. At least I could tell her what a hub cap is (was).