I seem to remember a combination of road surface, weight, tire compound etc will creat a dominant tire, one that tracks true and the other is left scrubbing... just ever so slightly. On both of my 923A1 trucks that happens to be the passenger front. Out of curiosity have you checked the alignment isn't crazy? Drive the truck in a straight line for 100 feet then try lining up your driver's side tire so that when you sight along it matches up with the rear's. When you have it perfect sight along the passenger side. You should not be able to see the sidewalls of the rear tires because now all of the tow in is isolated to the passenger front wheel. They should be towed in slightly to stop wandering with the steering. I found the 923 with the worst wear was towed in 3/4 inch at the outer edge of the tire. It sounds worse than it is given the given the huge diameter of the tires but still it is way more than plenty. Since they were easy to adjust with a big pipe wrench and I had nothing but time I tweaked it and drove it over the course of a day and got that down to 1/4-3/8. Very noticeable drop in tire wear but still tight wander-less steering. All big tires will wear sort of funny but it stopped taking the outer edge of the driver's side tread off and seems to be wearing more uniform. I put about 1200 miles on the tires (new tread but wicked old tires) to notice the funny wear, corrected it and put another 400 before I lost that tire to a side wall crack. Replaced both fronts with much newer tires, (again no wear) and have put another 800 miles on. They still seem to be grinding even. Just my experience. If you do it make sure your tires are always towed in, never out. Towed out tires will make the truck unstable whereas you can have crazy, visible tow-in and it will track smooth. If you check it and the alignment seems crazy you can always take it to a truck alignment place, shouldn't cost much. Bearings can also cause this but the level of damage leading to tire wear is normally apparent on inspection. As Coffy1 point out could also be a shock, unless the shock is leaking that cause might not be readily apparent.
Ken
