Tire experts? The boat has six of these #tires on it. They have a total of 3000 miles on them, mostly with the boat on board. They are labeled for max psi 80lbs and I just checked them all and found that they are all at 65lbs. I was going to bring them up to 70lbs but now I'm wondering if I should. After all, either they all lose pressure at the same rate (which is doubtful) or Discount Tire, where I had them installed while the boat was on the #trailer, set them to 65lbs for a reason. Opinions?