Wheels Articles Useful information

Centre Bore

Centre Bore

The centre bore is the size of the hole in the centre of the wheel where the spigot fits through.  The centre bore, (also known as spigot size), is the diameter of this hole, usually measured in millimetres.

Bolt Pattern/Pitch Circle Diameter (PCD)

Bolt Pattern/Pitch Circle Diameter (PCD)

PCD (Pitch Circle Diameter) is the measurement of the diameter of the imaginary circle drawn through all of the wheel bolts or studs on a wheel.  It is also known as the 'bolt circle'.

Offset

Offset

The offset of a vehicle's wheel is the distance between the centerline of the wheel and the plane of the hub-mounting surface of the wheel. It can thus be either positive or negative, and is typically measured in millimeters. Offset has a significant effect on many elements of a vehicle's suspension, including suspension geometry, clearance between the tire and suspension elements, the scrub radius of the steering system, and visually, the width of the wheel faces relative to the car's bodywork.