jur, I tried deflating and playing around with the inner tubes while deflated. I then re-inflated. The problem is less noticeable now. It is to the point where I can use the fenders without rubbing on the tires. I would not say that my tires are perfectly round by any means. My wheels might be a tad off too. I'm going to put some more miles on, and then re-evaluate the situation. Thanks for your advice. Thor included a couple of extra inner tubes with my seatpost, in case I blow them out.