PCD = Pitch Circle Diameter. It is the diameter of the bolt circle. In a 4-bolt configuration, this refers to the distance between the center of two diametrically opposite bolts (i.e. distance between bolt #1 and bolt #4).
Offset = The distance from the mounting surface to the rim's true centerline. A positive offset means the wheel is front of the mounting surface, closer to the center of the fender; a negative offset means the wheel is away from the mounting surface and projecting from the fender.
Last edited by Bogeyman; April 2nd, 2007 at 04:37 PM.