It seems simple eonough, of course most of us have made a mistake or two when tyring to determine what the propper stud spacing is for a given axle. To confuse things, GM has offered car axles that were of 5 lug designs in more thana one spacing configuration. Larger vehicles such as Cadillac’s may come with a 5x 5″ or the most commmon “Chevy” pattern of 5x 4.75″. Being that most cars run a 5 stud axle it’s just fitting that the measurement for the 5 lug happens to be the one that is hard to remember. So take a look at the proper way to measure a 5 lug axle before ordering custom wheels or axles. Its not center to center!