Actually, the stock rims on the AD trucks were 4 inches wide. Optional was the 4.5 inch wide ones, and the 15 inch rims resulted in the truck meeting the max GVW rating. GM changed from 6 clips to 3 at some point, I am not sure when, as a cost saving measure. The hubcaps stay on the same either way. But I have seen 15 inch rims with 6 clips.
