01 Excursion Limited, 5.4L, 146K Miles.
Firestone replaced my OE Load Range (LR) D tires with LR E tires when the tread began to separate on all 4 tires at 73,684 Mi. At the time the tires were replaced the tires were wearing normally and the tread looked as though if would easily last 100k mi. if it had not been separating. Now the LR E tires have 73K miles on them and they are showing signs of abnormal wear (in my opinion). I first noticed the wear pattern when they had about 50K mi on them. The inside and outside edges of the tread are wearing in a scalloped pattern between the inside and outside grooves on all 4 tires. The center of the tries are wearing beautifully and they look as though they could easily last 100K miles if it weren't for the inner and outer edges of the tires.
Since the vehicle was new, I have always kept the tires inflated to the pressures on the driver door sticker. For maximum passenger comfort and with 6 or less passengers and less than 300 pounds of cargo, Ford recommends 38 psi in the front tires and 45 psi in the rear tires.
I have had the tires rotated every 5K miles and the alignment checked and/or adjusted every 10K miles. They have occasionally adjusted the toe-in, everything else has always been in specs. The current shocks have 45K on them. The front wheel bearings are good, the ball joints are good and the truck steers fine and tracks in a straight line. I have never had these tires balanced since installation because I do not feel any indication of the tires being out of balance. It appears that these dealers are always trying to find something wrong with a vehicle when you carry it in for service and Firestone has never tried to sell me any kind of suspension parts or repairs.
Does anyone have any idea of what is wrong, should the inflation pressure be different for the LR E tires. Is this normal for tires with over 70K on them?

 

38-45 sounds a bit underinflated for an E tire...plus it sounds like you've got a normal underinflation wear pattern given the weight you're carrying on the tires (hard to tell without pix).
What PSI does the sidewall recommend at max load?

Typically, an E tire will have a higher max inflation recommendation than a D range tire...you don't neccesarily have to inflate to the max rating though since that's for max load. Without knowing what's stamped on the sidewall, I'd give a generic recommendation of 55psi. Watch the wear pattern and adjust accordingly up or down. And yes, the Es are gonna ride rougher than Ds even with the same PSI in em.

 

Max pressure on sidewall is 80 psi. I was beginning to suspect that it was a pressure problem but, when I asked Firestone, they told me alignment until I reminded them that I have a lifetime alignment contract with them and then they said it may be shocks or wheel balance.