I have an 03 Ultra. I have always run stock HD Dunlops. I can never get more than 8000-10,000 miles from a rear tire. I don't do burn outs or abuse them in anyway. I am not packing a bunch of gear and we are not large people. Most of my riding is done solo(back and forth to work). I put on around 14,000 a year and I have about 69,000 miles on my bike. 2 rear tires a year is terrible!. I have the tires mounted on the rims and then install the wheel and tire myself as I have for the past 35 years. The wheel runs true and swing arm bushings are good. I read about people getting 16,000 on a rear tire. What am I doing wrong???
Check this out:
Adjuster cam on baggers with this system - Harley Davidson Community
The consequence to a bad rear tire alignment will include lower tire wear mileage.
TQ