Bolt pattern, lug pattern, PCD, or bolt circle is the diameter of an imaginary circle formed by the centers of the wheel lugs. Bolt patterns can be 4, 5, 6, 7, or 8 and either holes or studs. The bolt pattern consists of two numbers - the first number indicates how many bolt holes or studs are on the vehicle, the other number describes how far apart they are in either inches or millimeters. A bolt pattern of 4x100 indicates a 4 bolt pattern on a circle with a diameter of 100mm. If you need assistance Measuring your bolt pattern please click here to view our Tech Tips page.