Having read all the threads in this forum on tyres I am still confused. My van unloaded weighs in at 550kgs/loaded 800 kgs and is fitted with 4 ply tyres. They are clearly car tyres made by Fulda. They are OEM. When they need changing is there any reason why I shouldn't get similar rated/specification tyres? I note that my car which is more than twice the weight of the caravan runs on 4 ply tyres.