[fiberglasscivic]

Do you live in an area where the weather changes a lot or where the temps between summer and winter are a big jump (like 90 avg to 10-02 avg.) If so that could be the culprit. If not then the only other option would be the age of the tire, even if it's only got 1000 miles on it, if its been on the wheel over 10 months then that could be the problem. It could be a combination of both.