Armed with the preliminary results from extensive testing and research, the Trailer Safety Industry Coalition (TSIC) hosted a half-day seminar May 16 at the Century Center in South Bend, Ind., to share information regarding wheel separation in the RV and related sectors.
Around 75 representatives from the supply, distribution and manufacturing ranks, including a significant contingent from the recreational vehicle industry as well as the cargo/utility market sector, reviewed recent study results measuring the forces acting on the joint mating the trailer hub and wheel.
Attendees also received data on the influences of surface contaminants, such as excess paint or grease, that can affect clamp retention, along with a detailed rundown on assembly procedures that can help prevent wheels separating from the hub, most notably proper and consistent torquing techniques. Representatives said TSIC will be issuing a publication approved by the American National Standards Institute (ANSI) on recommended assembly procedures and quality processes by the end of the year.
Bruce Hopkins, vice president of standards and education for the Recreation Vehicle Industry Association (RVIA) and co-chair for TSIC, said the coalition’s intent is to “proactively address a very complex issue” by taking the lead in establishing  recommended guidelines.
“The trailer industry is aware of wheel separation,” Hopkins said, noting that RVIA was joined by the National Association of Trailer Manufacturers (NATM), National Marine Manufacturers Association (NMMA) and National Truck and Equipment Association (NTEA) to comprise TSIC, which was formed to address the “wheel-off” issue – a potential concern of government regulators. “What we found out in the early going is that there wasn’t any existing research to show why this was happening. You also had a lot of different component suppliers involved, so it was important to establish a unified front where everybody was on the same page, which is what the coalition provided.
“Our goal,” he added, “was to be proactive in gathering data instead of dealing with some type of government regulation down the road.”
Behind the unusual meeting, in large part, was the National Highway Traffic Safety Administration (NHTSA), which had initiated several RV industry-related recalls. Richard Boyd, chief of the Medium and Heavy Duty Vehicle Division in NHTSA’s Office of Defects Investigation (ODI), delivered the keynote address at the seminar, outlining current findings while also explaining the agency’s responsibilities.
“The problem really showed up on our radar in the summer of 2004,” Boyd said, noting that ODI’s provisions for opening an investigation are based on the frequency and severity of failures. “Since then, we’ve conducted five investigations and three of those have resulted in the recall of 6,836 vehicles. Right now we’re concerned with the towable industry’s approach to design, product qualification, component selection and quality systems.
“The OEM has the legal responsibility for a recall. If there is a problem in the vehicle, we’ll be knocking on the OEM’s door.”
Boyd readily acknowledged the “cooperation” his office had received from the trailer industry to address the problem. “TSIC has really taken the ball and run with it,” he said. “I don’t foresee any type of government regulation at this point. I think that would just interfere with what the industry is doing.”
In response to the problem, the coalition conducted a study to probe the causes behind wheel separations. Around $175,000 has been contributed to the coalition to perform the study, including $80,000 from RVIA, $40,000 from NATM plus donations from other associations and component manufacturers.
The study, which included on-site testing of a fifth-wheel and cargo trailer at the Bosch Automotive Proving Grounds in New Carlisle, Ind., is being spearheaded by Columbus, Ind.-based wheel supplier Enkei America Inc. Ted Schorn, Enkei general manager for corporate quality and chairman of TSIC’s technical committee, offered seminar attendees an overview of the study’s initial findings. “One of our goals was to identify exactly what happens to the wheel-hub joint and the forces and moments that occur during operation,” he said. “We also wanted to provide a basic understanding of the ability of the joint to resist those forces.”
According to Schorn, test results showed:
   • Lack of necessary clamp load is the primary reason for separation. This loosening at the joint can occur during operation of the vehicle or through insufficient assembly practices.
   • Load assessment and component selection are important to maintaining clamp load.
   • Assembly process control is vital to preventing wheel separation.
Schorn identified several “critical” areas in the assembly process that could lead to wheel separation, including having a clean surface area at the wheel-hub joint, using a star pattern during the torqueing procedure and also using controlled, calibrated equipment.
He also emphasized the need for rigid and consistent quality controls, placing the burden on management to implement recommended assembly procedures while also following up through consistent auditing practices.
Schorn noted that responsibility extended beyond the manufacturing floor, as transporters and dealers also needed to be educated on maintaining necessary clamp load. “The TSIC activity is going to end up benefiting the industry greatly,” Hopkins said. “I think the fact that NHTSA isn’t planning to pursue any regulatory action indicates we took the right direction in being proactive on this issue.”