There is no doubt about it. Truck campers are heavy and most of us are probably close to the load capacity of our trucks. When it comes to load capacity, the limiting factor is often the tires. I k...
What is killing the tires is not the overload, as they can take 5 times the rated weight for rolling, but the heat. Heavy loaded tire flex a lot and that generate heat. Faster you drive - more heat is generated. When temperature gets at high level, the rubbers will deteriorate and then POOF. So observe your tire temperature on rest stops. Touch by hand is adequate. If you feel the tires too hot to touch- you better investigate and slow down.