Even though these are bias ply tires they should maintain a specific directional rotation based on which corner they are on. It has to do with the way the rubber was wrapped on the carcus and the overlaping of the tread belt. Here is valuable link. Those of you already with Avons & Goodyears might want to check it out. Thanks to Roger Kraus Racing.
http://rogerkrausracing.com/TechSheets/fit.shtml