I'd check your wheels for coplanarity first. Not the easiest thing to do either. I found a narrower blade can handle a misalignment better than a wide one.
Jason Holtz J. Holtz Furniture 3307 Snelling Ave. South Minneapolis, MN 55406 612.432.2765
-- Jason J. Holtz Furniture 3307 Snelling Ave. South Minneapolis, MN 55406