[asphaltgambler]

So..... I've performed alignments since 1981 professionally. I've used just about every type / brand of equipment and aligned just about everything that would fit on the rack. Further, I've studied this in depth and have attended a lot of training courses over the years. To the point that I taught other technicians 'the rope's' of the business of aligning vehicles. My specialty was problem vehicles that had been to other shops and end result was not satisfactory-or-where vehicles were heavily modified, like a 4x4 truck that was lifted with tall tires, which throws everything off from the manufacturer's original engineering of all the planes of angles working in unison. Specifically steering axis inclination along with axle centerline ( height) point of intersection with the center of the tire tread as it meets the road.

While the summation of this part of my career may or may not qualify me as an expert, at least possibly very experienced. One thing to remember is that when the vehicle is on the rack, all 4 wheels/ tires are sitting on 'floating' plates that allow the suspension to settle naturally.

Remember that the tire wear you see is a direct result of 1 or more angles out of spec, it is a reflection of what is wrong with the settings. Installing new tires w/o changing any mechanical settings will yield the exact same readings/ measurements as before as the vehicle is sitting on floating plates on the rack.

To the OP, depending on the amount and severity of the wear on the tires, the old tires CAN affect how the vehicle drives AFTER a proper alignment if not changed.