Strange tire wear issue
 

I have a 99 4wd Blazer with 180k.I have bad tread wear on the inside of my drivers side front tire. The passenger side tire is wearing pretty normal. I jacked up the front end one side at a time, starting with driver side since it has the wear problem. There is a little side to side play, but not much, and no up and down play. When I jacked up the passenger side, there was more side to side play than the driver side and still no up and down play.. When I bought the blazer, about 60,000 miles ago, I had a new steering box and pitman arm put on. Last summer, I replaced the wheel bearing and tie rod end on the passenger side. It seems the play is in the idler arm and that is what puzzles me. Can a bad idler arm, which is on the passenger side, cause the driver side tire to wear on the inside while not causing any significant wear on the passenger side tire? If not, does anyone have any suggestions?

Loose, worn, or out of adjustment steering linkage parts will cause toe to be out of spec, and wear will be the same on both tires. It will cause a jagged, symetrical pattern on the inboard or outboard shoulder of the tire. If camber or caster, or both, are out of spec on either or both tires, it can cause the vehicle to pull or drift to one side or the other. As you're driving, you hold constant pressure on the steering wheel to correct for the pull. This will straighten out one of the tires causing only one to wear. Best to have it checked out by an alignment shop.