These wheel nuts correspond to part number 4895430AB. I have used them on 18" steel wheels with police pack center caps - part number 4895432AA. These nuts have a smaller diameter collar over the tapered seat that allows the center cap to snap onto them and secure them to the wheel. Force to snap the center cap into place - judicious use of a rubber mallet will help. Ring nuts on aluminum rims have a larger shoulder and hub caps do not fit.