Tire fitment/ bed width?

[skoffice]

Hey guys, I have the bed off of my fleetside at the moment and in pieces. I was wondering if anyone had the measurement, or could check sometime tomorrow what the width is to the insides of the outer fenders? I realize they curve in as you go upward but if I can just get the measurement to the top inside of the wheel circle I can reference from there. My rear end is pretty much done and shortened a couple inches, and I'm doing a semi back-half. I was going to get started on figuring wheel width and backspacing but I forgot to measure the bed, Doh!