A few wheel underlays I messed with tonight. Most images from deviant-art, several created by myself. Trying to mix it up, the single semi circle is kind of boring to me, hopefully some of these are useful. Let me know your favorites and any suggestions for more you may have!
Copy your desired underlay image to PinballXMediaImages DIRECTLY, replace the existing underlay.png if it exists, and rename the new one to underlay.png