Alfa 166 2007

PCD and centre bore

PCD describes the number of fasteners and the diameter of their bolt circle: for example, 5 × 100 means five fixing positions on a 100 mm circle. Centre bore is the opening that locates the wheel on the hub. A matching number of bolts alone does not establish compatibility.

What offset means

Offset, often marked ET, is the distance between the wheel centreline and its mounting face, in millimetres. Along with wheel width, it affects the position of the wheel relative to the suspension and bodywork. Check front and rear requirements separately where listed.

Before fitting replacement wheels

Confirm wheel width, diameter, load rating, brake clearance, tyre compatibility and the correct fastener seats and lengths as well as these measurements. A blank value is unknown, not zero. Sizes grouped together share the recorded figures; that alone is not approval to interchange complete wheel assemblies.