Thanks for thye fast replies.
I mounted up two of the tires on the 15x10's front and rear. In the rear, If I hit a big bump, flexed at all, I would relly chew up the fender. The tire sticks out ~3in. past the fender.
In the front, I hit in the front fender, but since it's only plastic, a little trimming and i'm in the clear. The rear of the front fender is the problem. because of how far the tire sticks out, it is really hitting bad. I tried to pull the fender out to see what was under, found black plastic trim, and metal. If i cut this, i lose my mounting point for the bottom of the trimmed fender.
I am just hoping that narrower wheels with more backspace will help get the tires in closer to the body, reduce the amount i have to cut.
Remember, this truck floats, not flexes.

Thanks, Ted