26x11.5x15 Hoosier QTP ? Please help

Over 1 inch to my spring. Sorry I didn't get back to you sooner. Measure your closest point on iner fender well be it the spring or the iner fender itself to where the rim sits flat on drum or rotor. That tells you room in rear. I had 6 inches to spring so I did 4 1/2 backspace and I had 5 to fender lip .