If you are replacing an existing set of baby moons, the easiest way to determine the size is to just take one baby moon hubcap off of the wheel, flip it over and measure the inside diameter of the cap. If you don't have existing moons, then use the instructions below.
* Important Note:
Instructions below are for wheels with 4 Nub center cap Hubs.
"But my Hub has 3 Nubs" Click Here
Step # 1: 3 Nubs
Measure Nub tip to Nub tip on the rim as shown in the diagram above.
Use the chart below to help you determine which size baby moon your wheel requires. These baby moons only come in one of the 6 sizes shown in the chart below.