To identify the correct hubcap manually you need three basic measurements:

1. Number of bolts:

Count the holes.

2. Size of the bolts:

The cross-section of the threads in inches to the nearest thousandth (e.g. .313).

3. Bolt circle diameter:

On a hubcap with an even number of bolts, simply select two holes opposite one another and measure center-to-center.

On a hubcap with an odd number of holes, start by measuring the center opening (A) and divide it in half.

Then measure the distance from the center opening to the center of one of the bolt holes (B). Add A and B together and double it for the diameter of the bolt circle.