16.5 wheel hitting rear brake drums

[bluek5]

So I had a bright idea to put some 16.5 x 8.25 wheels on one of my Blazers. While I was tightening the rear wheels they did not seem to be tightening down soon enough. I thought maybe they were tight on the center of the axle. Anyway I went for a ride and could hear grinding noises coming from the rear end. I crawled under to investigate and it appears that the outer edge of the drum is in contact with the wheel. This is deforming the drum pushing it into the backing plate. I am just interested if anyone has experienced this before.
Thanks, Paul