Thanks for the replies, I did take all four wheels/tires to a tire shop and asked them to first check the wheels for true and out of round, then balance. They said they are fine, 2 of them were only slightly out of balance. I kinda was thinking I should just do the whole job at once, probably will proceed this way. As for previous maintenance, I have a lot of the receipts from the previous owner (original owner), but I feel that he only did what he had to. Thanks again. Brian