Gonna reheat this thread for one item I didn't see directly addressed.

I just got (as mentioned elsewhere) a new set of Michelin LTX M/S2s in 255/65R16 put on my factory alloys. They set them to 40/40, as Mike suggests. But they also told me the recommended pressure (according to whatever source fed their computer) is 26/42.

I've noted that the steering tracking seems a bit squirrely on the new tires, and since all the sources seem to agree on 26psi-ish for the fronts, am I getting an appreciably smaller tread patch up there at 40 that might account for that?

 

40/40 isn't causing you to get squirrely, with your mileage I bet there is a few warn out steering parts that is causing this.
The only reason Rover set 26 for the front was for a better ride at the expense of lower MPG and excess tire wear.

 

Got it.

I *think* I did all 5 when I put the OMEs on in mid '10, but I might be wrong. I assume that's the first place to go, if not?

 

Dan, I also run the (255/55R18) Nitto Terra Grappler on my 2002 Disco II. Over the past 5 years, I get the best gas milage and ride with 30 psi in the front and 40 in the rear. Tried the recommended 28 in the front and wore those out after 15,000 miles. I have 28,000 on this set with plenty of tread left

 

Ok.. to simplify this whole thing , every tyre brand is different in some way , example in your case 255' - some are moulded round , some are a bit square, and strange enough some are even a few mm's wider .... the side wall on some are softer , some are more re-enforced ,( for off road applications ) etc, then you have the texture... some are soft compound ,which is great traction , but shorter life , some are harder compound which is not as sticky with traction ( asphalt road ) but would last longer , and would be better on un-even terrains , so basically their are Passenger Tyres , Off road tyres and Commercial type tyres .

To each its own purpose ,,,,,,,,, tyre pressure now.......
if you have 30 psi on the front of a regular LR , tyre shape would look normal , if you put 30 psi on a LR with a winch on the bumper , it will look flatter and under-inflated ...

So no tyre pressure is correct or in correct at the end of the day , ( My Opinion ) the reason i say this , and you can ask the guys who go off road , its recommended to lower your tyre pressure , for better traction in the mud , a softer tyre gives you a better foot print , you can only determine this based on your loads and terrain ( i run 15 psi off road , on road 30 psi , )

give or take a few pounds can never cause your tyres to wear unevenly short term , bad alignment and camber is more critical for wear , so don't loose sleep over it ....... you'll go crazy .. One Life to Live , Just Live it .