I keep having pretty significant leaks on my Buick where the tires meet the alloy wheels. I'm dropping down to less than 20 psi in maybe a week. I get my tires rotated and balanced for free at tire discounters as part of the package I bought when I got them installed. About every other time I go for rotation I tell them and they will usually grind the inside of the wheels and it seems to help for a few months but always comes back. I have been wondering if there's anything else I can do. I don't think I will be able to get the tire shop to do anything differently so I just wanted to hear some ideas.