I have zero problems with 38x15.50's on a 20x9 wheel, got side wall bulge but also good flat tread. I love the look too. I would prob go taller and more narrow next time though, just a lot of tire.
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07 2500 4x4, 6.7 auto, Pioneer Navi, factory remote start, XRT, Edge HOT, Airaid Intake, H&S 5" tbe w/6" tip, egr delete, leveled, 35" FC-II's on custom 20" DC-1's