Truck Pulls Right - Process of Elimination?

Had the same thing happen to a truck I was driving. New steer tires and it pulled to the right bad , I talking better not let go of the wheel or you'll be heading for the ditch. Checked a lot of stuff, didn't fix the problem. Boss just couldn't believe it was the new tires. We took them off and put them on a truck he was driving. Same thing. He sent them back and bought a different brand. For the life of me I can't remember what brand they were