My new sundance came with goodyear marathon load rate E 16" tires. After reading the horror stories on all rv forums about tire blowouts I decided to inspect my tires closley. I noticed that both tires on the door side have an indention in the side wall that runs from the rim to the tread. The indention looks like a small "valley" 1-2" wide and just deep enough to notice. you can feel it with your hands. I can't get to my other two tires right now because the slideout is out, I will check them tonight. Is this a problem or part of the design of the tires?