[RhoXS]

Over the past 45 years I have periodically run into this problem on various vehicles. Without exception, after it is aligned, and all possible mechanical issues have been ruled out, it ends up being caused by something the tire shops call a "radial pull".

Swapping the front tires sometimes solves the problem. Replacing the tires always, without exception, solved the problem for me. The amount of or lack of obvious tire wear does not seem to matter.

I understand the radial belts sometimes slip or slightly move out of position. This changes the rolling resistance compared to the other tire. Therefore there is a slight pull. I do not know if this is an accurate explanation but I have heard that said a number of times.