I just got some LR E tires for my F150 because they didn't have them in LR C and the price difference was only $2 per tire and I wanted them installed that day.. :)
Anyway, I've had them about 2 months now. The tire store (Les Schwab) had them at #35 on all 4. It rode better than the old C's did, but the fronts had too much of a 'bulge' to them for my taste.
I upped the fronts to #44 and the rears to #40, which is what I ran the old C's at and it's fine for me.. Sure, it's not a cushy Cadillac ride, but it never was and it's a TRUCK! :)
I know you have the Expy and it's supposed to be a bit more "cushy", so you will probably need to find your own PSI that works for you, but you should not have any issues running them at #35 for everyday running..
Good luck!
Mitch
