The tyre treads a displacement map. Essentially, he tyre was geometry was rendered using 2 different shaders. This workflow was chosen as was the easiest way to create a uniform tyre tread pattern, while doing a flat projection texture for the tyres walls.
The tyres were used in a final render that was a Camera Projection and Vray test located here.
Below is a link to an example hip scene:
Note: no source images for the shaders have been included.