Actually there may be three labels attach to your RV trailer that provide a lot of necessary and safety information. The most prominent is the federal certification label. For RV trailers its permanently attach to the forward LH external section of the trailer. Along side of it there is normally a tire information placard. Inside of the trailer normally inside of a cabinet you will find a cargo information placard.
The federal certification label will list the trailer’s VIN, GVWR, each GAWR, the tire and rim sizes installed as Original Equipment (OE) and spares along with the recommended cold inflation pressures for those tires.
Nowhere in the regulations does it say users/owners may select tires to match the vehicle’s GAWR. The vehicle manufacturer fitted the OE tires that were appropriate for that vehicle and therefore they become the minimum standard for that vehicle. Plus sizing them is OK, minus sizing them is not ok. For RV trailers read FMVSS 571.120 and all references within that regulation.
Note: The National Highway Traffic Safety Administration has a legislative mandate under Title 49 of the United States Code, Chapter 301, Motor Vehicle Safety, to issue Federal Motor Vehicle Safety Standards (FMVSS) and Regulations to which manufacturers of motor vehicle and equipment items must conform and certify compliance.
If an owner knows what is considered safe or unsafe and chooses the unsafe over the established safe the consequences are his to bare.
I present the safe side of things. Sometimes unpopular and misunderstood. The misunderstandings are normally caused by who does what. The FMVSS sets the minimum standards for vehicle manufacturers. Industry standards are, for the most part, established by the Tire and Rim Association (TRA) and the Rubber Manufacturers Association (RMA). NHTSA provides safety info via their SAFECAR publications which follows along with industry standards. You’re not going to find much in print on the WWW by the TRA because a lot of their information is confidential within the industry. The RMA has a four chapter document in PDF format on the WWW that is very informative and useful to all. Here is the link. Chapter 4 is the RV application.
This is my last post in this thread. If you want a specific reference PM me.