Ah! Dually! My experience is with single wheel axles.
Spec sheet for your rig states it's a 6.75" rim width for a 245/70Rx19.5 tire. Offset is 5.50". However, it also states it's a 10 lug for the 19.5 and 8 lug for the 22.5" wheel.
I'd be sure you have the right wheels on there to begin with. If you are running 19.5's on 8 lug, there could be a safety issue.
Found info here on page 15;
https://www.fleet.ford.com/truckbbas/topics/2017/2017_F53_F59_Specifications.pdf#page=2&zoom=auto,-9...It's a 2017, but I don't think the wheel specs would have changed.