I was [still am sometimes] a tyre fitter car&truck seen this often the paint flakes off the bead when it doesnt get used every day the alloy wheel corrodes ats and most of the other tyre companys dont use tyre grease they use tyre soap for fitting the tyre and it doesent help the problem you cant use normal grease it will eat away the rubber the best thing to do is if you cant get tyre grease is take the tyre off and wire brush and spray paint the bead hope this helps