Both P Tires and the LT tires are actually different types and kinds of tires. The P kind of tires refers to the Passenger tires, that are tires used for passenger vehicles, while the LT types refer to the Light Truck kind of tires. P tires are very much flexible than the LT tires. LT tires ride so rough than the P tires. The P tires ride very smoothly on the roads. The LT tires are very much strong when compared to the P types.
The LT tires come with maximum inflation while the passenger tires do not. Light Truck tires are really made of treads that are more aggressive than the Passenger type tires. The light truck tires are way stiffer Gan the passenger type tires, which are really less stiff than them. LT tires do have a load range of 10 ply, while P tires only have a four ply load range.