I had cupping issues a while back on the front tires....I rotated them to the back and the wear evened out. Same time, did some research that it could have been, and ended up being the problem, but it was the result of the front shocks getting weak and wasnt controlling the everyday road rebound correctly, ie, bumps, pot holes, uneven road conditions. Changed the shocks and havent had an issue since.
As long as it's down hill 
129 MPH!!! 