Agreed on the “no rusty wheels”. I’ve been working on prototypically modeling/weathering wheel faces for solid bearing trucks recently. Every time I think I have an accurate and easily reproducible method, I find another well-lit photo illustrating some new oil pattern. In this case, it was the radial streaking - different than the more common “soft” circumferential wicking from the hub outward and tire inward. 

This wheel face is relatively clean - maybe there simply hasn’t been enough dirt/dust yet collected to absorb and distribute the oil more evenly. In any case, another well-lit reference. 

Matt Goodman

Columbus, Ohio