I have LT245-R16 load range E on my 1 ton Pleasureway. I work in the construction industry and we run 1 ton & 3/4 ton trucks pulling flatdeck trailers. We use the LT load range E's on all our trucks and trailers. LT stands for 'light truck'. P stands for passenger. LT's come in different load ranges. Load range C is 6 ply and 50 psi max. Load range D is 8 ply and 65 psi max. Load range E is 10 ply and 80 psi max. Side walls on C and D are only 2 ply and E is 4 ply. The E tires give a bit stiffer ride, which is good for handling in winds, but a bit rougher ride. I would definitely not use P rated tires on any van, trailer or motorhome, and would at least use LT with D range as a minimum. In hot weather, if your tire is underrated for your vehicle, the side walls may heat up to the point of exploding. It's not worth the risk to run tires like this. Any tire shop should be able to tell you what weight rating you should be using.