What do I need to run dually wheels on my F250 2003?

Are you talking about the wheels or setting up a full dually? In 2003, there wasn’t much difference between the 3/4 ton and 1 ton. So, if you’re just putting some Alcoa’s on the front, go for it. But for the back, you’ll need single Alcoa’s or swap the entire rear end from a 350. And don’t forget the rear fender flares or it’ll look bad. For context, F150 is 1/2 ton, F250 is 3/4 ton, and F350 is a 1-ton truck.

Ryan Reynolds: “But why?..”

You need two more tires for the rear axle.