Measuring 3 piece wheels can be a bit more complex than measuring traditional one-piece wheels, as 3 piece wheels are made up of separate rim, spokes, and center components. However, with the right tools and knowledge, it's not too difficult to get accurate measurements for your 3 piece wheels.

The first step in measuring 3 piece wheels is to gather the necessary tools. You'll need a tape measure or ruler, a caliper, and a wheel backspacing gauge. The tape measure or ruler is used to measure the overall diameter of the wheel, while the caliper is used to measure the width of the wheel. The wheel backspacing gauge is used to measure the distance from the backside of the wheel to the mounting surface.

To measure the overall diameter of the wheel, place the tape measure or ruler along the outer edge of the wheel and measure the distance from one side to the other. Make sure to measure in a straight line and to account for any protruding spokes or other features.

To measure the width of the wheel, use the caliper to measure the distance from one inner rim edge to the other. Again, make sure to measure in a straight line and to account for any protruding features.

Finally, to measure the backspacing of the wheel, place the wheel backspacing gauge against the backside of the wheel and measure the distance from the mounting surface to the backside of the wheel. This measurement will give you an idea of how much of the wheel will be visible once it's mounted on the car.

Overall, measuring 3 piece wheels may require a bit more attention to detail than measuring traditional one-piece wheels, but with the right tools and a little bit of know-how, it's not too difficult to get accurate measurements. Whether you're looking to upgrade your wheels or simply want to make sure your current wheels are properly sized, measuring 3 piece wheels is an important step in the process.