I have a 98 Ranger 2 wheel drive. It has 185,000 miles. The front end is completely tight. The ball joints (all four of them) and the steering rack rack have been replaced. The truck has no caster or camber adjustment, only toe in. I have set the toe at 1/16" toe in. I have replaced both front rotors and washed and repacked the wheel bearings. All of this has been done within the past year. The tires are new as of this past spring. I had them spun balanced and there is no shimming or shaking at all. It just passed a state inspection and, as mentioned above, the front end was completely tight. What would cause only one front tire (left) to cup on the inside edge. It has been doing this for a long time.

 

How old are the shocks? Have seen bad ones cause tire wear. Seems like you have covered all the other bases.

 

What brand of tires?

 

Currently I am running Firestone 215/70R14. The original size calls for 225's but I can save about $30.00 per tire by going one size smaller. (It also gives me more power on the hills) My truck has been wearing the left front tire for a long time.(100,000 miles) I have run several different brands of tires. All I do is keep them rotated when they start to show cupping. The shocks seem to be OK when given the bounce test and, as pointed out above, the truck passed the annual state safety inspection and shocks are on the list. They have been replaced with original Ford shocks but it has been quite some time ago.

 

Replacing shocks on my 98 4x4 took care of this problem of for me. They also seemed to be OK with the bounce test, but had 160,000 km on them so I replaced them as preventive maintenance. As a fortunate side effect my tires stopped cupping.