I have a set and they are night and day difference when hauling. I don't have a compressor or tank on my truck but my loads usually don't change. The load I leave the house with is what I have the whole time the trailer is hooked up. On the occasion when I head out empty to pick something up I normally just put about 50 psi in them and works out great. I haven't ever put more than 60 psi in them before, and thats with about 15,000 behind me mostly. You can normally buy a whole kit for around $450 from what I've seen online and thats with a compressor