I made mine from a 3/4" 7075 aluminum plate, I took a scrap piece out of the trash, that was 1.5 x 14.00 long and sawed a slot wide enough to fit (we use a 3 or 5 tooth per inch wood blade) at an angle, then sawed away what was in the way, then belt sand it smooth, then take your time and walk your way around the lip. then you can make a different angle on the other end, to move it more, if need you need to. It was free.

You can go to the scrap metal dealer and get sawed scrap cheap.

I have 295x55x15's on 9" wheels on the rear of my '87 Mustang that just touched.

Pat