HELP! steering pull issue!

[Yetti]

you might try crossing the tires from one side to the other? if it follows the tires you found the issue.
I have seen many a tires cause this because the belts have a slight tapper to them and create "radial pull".

if you should find this rotate it to the rear and let it wear back there. most likely it won't effect the vehicle from the rear because it can't force the steering. also make sure the tire pressures are all equal. that can make a little problem a big one.