Unknown to me, the rear fork bearings wore out - both were ripped apart. I had been adjusting the belt to this and continued a ride hard into blemished trails. The belt held up to tremendous load and showed no wear for the worse. But after another 10,000 miles, chrome on the rear pulley flaked enough that I changed it out, and put on a new belt also.
That was the second pulley I replaced with about half the chrome flaked off. Harley now leaves the chrome off!