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ST tire failures
You know, I’ve been writing about RV trailer tires for more than 17 years. I’ve explored, reviewed, researched and written about thousands of tire failures that occurred while in use as RV trailer tires. Many of my conclusions are drawn from multiple failures from single causes although unknown by the consumer.
When reading this please take into account that I’m a serious study of the rules, regulations and standards used by the industries that have approved the tires for use as high speed trailer tires. I’ve read ever DOT/NHTSA tire rules committee report, approval/disapproval since 2003. I’ve read some of them so often I can reference them without rereading them (again).
The evolution of ST tires used on our RV trailers is directly linked to the needs of the trailer industries. As more and heavier trailers were built, the ST tire manufacturers were being driven to provide more designated sizes and load ranged tires to support the demands of the trailer industries. Because of import/export rules, almost all of the off shore ST tire manufacturers have always had a huge advantage in pricing, which (IMO) caused almost all of the USA manufacturers to not waste their time building tires that were going to be very difficult to sell to a market that had numerous tires on their USA shelves at much lower prices.
The Tire and Rim Association (TRA), an organization with approval authority for the construction and standardization of the ST tire design, set a 65 MPH maximum operational speed restriction for all ST tires. Because there is no official speed letter for 65 MPH, there was no authority to force those manufacturers to provide that information on the tire sidewalls.
Enough lead-in info, let’s get to the meat of the posting. I’ll add references as I go from here.
So, where do RV trailer manufacturers get the tire/wheel assemblies, suitable for fitment to specific RV trailer axle loads? They get them from suppliers of OEM equipment. The tire is from a tire manufacturer and the wheel from a wheel manufacturer. The tire manufacturer provides the installers with approved rim sizes for the tires. Load and PSI needs will be provided by the needs of the axles they are earmarked for. Yup, were getting to some of the meat. The OEM provider will almost always assemble the wheel/tire assembly to a request made by the vehicle manufacturer. If the vehicle manufacturer’s request has not provided a PSI setting for the assembly, the tires will normally have the PSI value used to set the bead. If the factory installer fit's that assembly to an axle without a PSI request from where it’s going to be fitted to a vehicle, it will still have that bead setting PSI in it. Eventually, as the trailer progresses along the production line the tires will become overloaded. If at final vehicle certification the pressures are not increased to recommended cold inflations for the fitment, the trailer will be turned-over to a delivery agent. Will the agent inflate to recommended cold? The tire damage started just as soon as it became overloaded. It could then be more severely damaged by being severely under inflated for transport and having its delivery speed increased beyond 65 MPH. Once at the dealer location it will continue to degrade from overloading until someone discovers the under inflated tires. The damages have been done. Tire damages are cumulative. Those tires are going to fail long before their predicted life span. Maybe that will happen on the way to their new home.
If you want an installment 2,3,4 etc.. Let me know. I’ve just barely got in the door
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