15x8 wheels are good for 10.5 or 12.5 width tires. The back-spacing on the factory Canyon wheels is the issue. They will work fine with a 31x10.50 or 33x10.50 tire, but a 33x12.50 or even a 32x11.50 tire will rub unless you run wheel spacers. The factory wheels have close to 5-inch back-spacing, while most aftermarket wheels will have 3.5 to 4.25 inch back-spacing, which will accommodate the wider tires without having to use spacers. One of our TJ's has 31x10.50's on the factory Canyon wheels, and the other one has 33x12.50's on Ion alloy wheels, and neither has any rubbing issues.