Running 4.00 x 8" LOADSTAR on my Starlight Trailer. I put them on new about 5,000 miles age. They are near smooth in the middle 2", some thread on the outside 1" on each side. I started with running 20psi, (the center really wore fast) dropped to 12psi the last 3,000 miles, they wore a little better. For those running 8" tires, please give me your milage and tire pressure you run. I hate to go much lower on pressure in being afraid to break a bead if I hit a sharp bump etc.