Wrapping around a circle

I have an object like this


I want to wrap it around a circle. What would be the easiest way to do that. It is going to be a tire.

Use the Warp feature. In edit mode get into the view that would be the side of the tire. Move your tread mesh down from the center of the grid and then press Shift-W and move your mouse to warp the mesh. You can find a better description of this tool in the wiki: http://wiki.blender.org/index.php/Manual/Basic_Mesh_Tools#Warp_Tool