Replacing the rear tire on the Vstrom at about 7000 miles due to a nail puncture. While looking at the tire, noticed that they are wearing in a really odd pattern. They are all cupped and have bumps on them, much like a car that has a bag alingment in the front end. Is this a normal thing, or is it just something that the Trailwings do? Have also been noticing a howl going around corners that I believe is caused by the cupping of the tires. Can anyone shed some light on this? Thanks!