OK, I'm going to go and measure it now. I'm getting 5.5" inches from the wheel mount on the brake drum, to the leaf spring. Wheel mount to tire edge is 4.5 " laying flat on the floor. But on the other side with the wheel on, still have 1.5 " inches to the spring. So it looks like I can do a max backspace on the wheel of 4.5 to 5".
