Originally Posted by Gyrogearloose
The problem I'm pointing at is that there is no margin in some Forest River products between the tire load rating and the estimated applied load. The absence of a margin means that individual tires can be over loaded for a host of possible reasons like production differences in axle force constants, or like additional loading as weight shifts on curves.
That Forest River can get away with doing this may indeed be a flaw in government supervision. The NHTSA is overworked and probably misses a bunch of problems as a result. This shouldn't change the ethics of selling a product that is potentially unsafe.
As a consumer who purchased a Forest River product, my focus is on my trailer and its manufacturer. I believe that my trailer will overload the tires due to weight transfer to the outside wheels when I am driving reasonably on a winding road. As a consumer, I view this as a product defect and safety issue, irrespective of whether the governmental agencies have noticed it.
And, it occurs to me that if Forest River is aware that tires can be overloaded when their products are otherwise being used in a reasonable manner, and if someone ends up seriously injured or killed as a result, this is likely to result in significant liability to FR irrespective of governmental supervision.
Flawed rules are the same for all RV trailer manufacturers. I doubt that FR can be held responsible for following the rules as they are presented to them. To do so would severely impact their ability to compete with other like RV trailer manufactures.
These are out of context quotes from one of the tire safety regulations.
1. The sum of the maximum load ratings of the tires fitted to an axle shall be not less than the gross axle weight rating (GAWR) of the axle system as specified on the vehicle's certification label.
2. The size designation and the recommended cold inflation pressure for those tires such that the sum of the load ratings of the tires on each axle is appropriate.
3. The size designation and, if applicable, the type designation of Rims are appropriate for those tires.
4. On RV trailers, the sum of the GAWRs of all axles on the vehicle plus the vehicle manufacturer's recommended tongue weight must not be less than the GVWR. If tongue weight is specified as a range, the minimum value must be used.
5. The UVW and the GVWR used to determine the RV's load carrying capacity must reflect the weights and design of the motor home or RV trailer as configured for delivery to the dealer/service facility. If applicable, the weight of full propane tanks must be included in the RV's UVW and the weight of on-board potable water must be treated as cargo.
Other safety regulations govern equipment testing resulting in certification. Tire certification testing is normally done by a third party but can also be done by the individual manufacturer or at a NHTSA testing facility. Not all tires in a batch/lot are tested. It’s a random procedure except in a recall situation unless the cause for the recall is known.
The nitty-gritty: Regulations for Automotive tires provide reserve load capacities beyond a vehicle’s GVWR. In the same regulation RV trailer tires are not required to provide any load capacity beyond GAWR. It was hashed over in the last round of the rules making process but no action was taken.
Morally (IMO) its wrong for a RV trailer manufacturer to put two 3000# tires on a certified 6000# axle. Its been done and will continue to be done as long as the current regulations remain unchanged.
Usage safety regulations are written for an end item such as a tire. Engineering of that tire is what got it on the market in the first place.