Your comparing your 6 to your 12 thats a big difference in rwh, the bigger bike will eat tires when out playing. And they ment for that bike to have all it power in the mid range I bet in the 1500 miles you put on you were pretty heavy on the throttle. Things to think about what were your tire pressures, if you were running them lower for grip that'll speed the wear up. And it looks like they made 2 different versions of that tire, the one for the bigger bikes probably was made to have more grip for the added power and torque. If you want them to last your going to have to stay out of the throttle. Or try different tires like a multi compound, just remember if you choose to go more toward the touring tire your level of grip drops off. I go threw 2 rears to 1 front in a year, I change my own tires and run race take offs. I can get almost 1500 miles out of a rear, im a licensed expert road racer and my street pace with my wife on back is probably faster than most would ride by them selves.