The F9 housing center is as burly as it looks, and is made from Hi-Form 50 steel. It's made to fit 3- or 3-1/4-inch-diameter axle tubes. We went with 3-1/4 inch, 0.250-inch-wall tubes. Stock width is 66 inches from wheel mounting surface to wheel mounting surface, and you can get your Toyota F9 in stock width. We wanted to go wider with the rear because our Total Chaos long-travel front end is 3-1/2 inches wider per side. It's best to have the rear end be slightly narrower than the front, so we chose 2-1/2 inches wider per side, or a total of 71 inches.