i finally broke down and am putting a new rear tire on the gl500. but once i had it off i observe a strange feathering tire wear pattern. the center is bald as is obvious but a close look at the edges shows each individual segment of tread is worn like a little ramp. does anyone know what causes this? tire has about 2400 miles on it and i carry a lot of weight in my homemade trunk and ammo can side bags.