Station VII:
Bolt Pattern

Pitch Circle Diameter (commonly called the bolt pattern) uses a two number system as seen on the pictures on the left and right.

The first number is the number of holes

The second number is the diameter of an imagnary circle that would have the holes on its circumference

IF there are an even number of holes, then the PCD is easy to measure, simply measure from centre of one hole to the centre of the opposing hole.

IF there is an odd number of holes, it is a little more complicated ... look at the image below:

Using Measuring Tape

To avoid any sort of error in measurement, a PCD gauge can be used by simply placing the tool into the closest pair of holes.

The sliding scale will give you the correct diameter for the circle of holes.

As seen in the gauge to the left, there are multiple scales based on the number of lug nuts (holes in the rim).

The diameter for the PCD can be found in the window under the right hand tine,

In this station you will be measuring the PCD using both methods:

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