The trick setup for C2s was the optional cast-aluminum knock-off wheel package. The knock-off design was racing inspired, with the wheel held on by one large nut fitted with a spinner that could be removed with a mallet. The '63 design had either two or three wing spinners, but the ribbed aluminum wheel itself stayed basically the same from 1963 through 1966. The design radically changed in 1967 into a "knock-off-style" wheel. Due to safety concerns, the centersection of the spinner hub was actually a cap that covered a standard five-bolt pattern.