As trailers evolve into multi-purpose vehicles, it is even more important that there is a standard to define the minimum requirements for critical trailer components, allowing them to be evaluated without bias, according to Tom Romero, director of training and education for Cequent Performance Products.
“A standard provides a way for industry to have assurance the products they specify, buy, build, and sell adhere to minimum requirements as established by unbiased professionals,” Romero said. “As capacities of trailers increase and more burden is put onto individual components, it is important that there is a standard to ensure consistent performance of the components.”
Frank Drake, director of engineering of trailer products for Cequent Performance Products, said that regulatory authorities may use this standard to formulate regulations and although SAE does not make laws, “sometimes a muni like a state would adopt an SAE standard into their requirements so that it effectively becomes a law.”
Romero said SAE J2638 is both a static and dynamic testing that includes 300,000 test cycles for each test condition—vertical, longitudinal, and transverse.
The static performance criterion is no loss of attachment, meaning the gooseneck coupler cannot come free from whatever it is attached to and must maintain each load for five seconds. The dynamic performance criterion is that there is no loss of attachment, the load is maintained throughout the test, and the test specimen must be able to couple and uncouple after the test.
The VR (rated vertical coupler load) is specified by the coupler manufacturer. The gooseneck coupler adjustment must be at the maximum stress position. A single sample must pass three directional dynamic tests, 300,000 cycles in each direction, and 900,000 cycles total.
Identifications and marking for the pin box or gooseneck: manufacturer’s ID; maximum trailer GVW; rated vertical coupler load; and nominal gooseneck ball size.
Identifications and marking for a removable gooseneck ball: manufacturer ID; maximum trailer GVW; and nominal gooseneck ball size.
Romero said gooseneck couplers with a load-bearing pin and set bolt(s) provide the ultimate solution:
• A load-bearing pin provides vertical load carry.
• A load-bearing pin prevents the inner tube from sliding downward or upward under the vertical load.
• Set bolts eliminate the rattle, movement of the inner tube, and provide less chucking while towing.
Possible issues that could occur with gooseneck couplers without a load-bearing pin: improperly torqued set bolts issues include over-torqued set bolts that can cause damage to the inner tube (fracturing) and under-torqued set bolts that can allow the inner tube to slide up inside the outer tube, causing damage to the inner tube and loss of height adjustment.
Additional gooseneck coupler features to consider:
• Greater articulation between the gooseneck ball and coupler while traveling over rough terrain. “This is how in many cases the trailers are used, so that greater articulation is going to create less wear and tear and be a lot easier on all towing components,” Romero said.
• Easier coupling and uncoupling.
• Increased range of height adjustment to accommodate today’s truck heights. “That’s another issue in the marketplace today. As trucks get taller, we need that increased range of height adjustment.”
Drake said Cequent Performance Products’ BX1 premium gooseneck coupler includes: a load-bearing pin; greater articulation between the gooseneck ball and coupler while traveling over rough terrain; easier coupling and uncoupling; and increased range of height adjustment to accommodate today’s truck heights.
Romero and Drake also talked about the standard for pull-behind trailer couplings, SAE J684 (Trailer Couplings, Hitches, and Safety Chains).
This Standard includes couplings, hitches, and safety chains used in conjunction with all types of trailers or towed vehicles whose Gross Vehicle Weight Rating (GVWR) does not exceed 10,000 lbs.
This includes most types of trailers normally towed by conventional passenger cars, light-duty commercial vehicles, light trucks, and multipurpose passenger vehicles. It is primarily intended for ball and socket type couplings and hitches.
Romero said a weight-carrying hitch is a mechanical and/or structural device that connects the trailer to the towing vehicle and does not employ features designed to redistribute the load imposed at the hitch and coupling connection. A weight-distributing hitch is a mechanical device that connects the trailer to the towing vehicle, and by means of leverage applied on both trailer and towing vehicle structures, when properly adjusted, distributes the imposed vertical load at the hitch and coupling connection between structures of the towing vehicle and trailer.
He said there are two types of strength requirements for the ball and coupler in J684:
• Attachment of coupling. Bolting, welding, riveting, etc, and the coupling attachment must safely withstand the prescribed loads.
• Strength test for couplings and balls. Couplings and balls must meet the minimum standards.
Couplings must be permanently marked with the following: SAE classification and trailer GVWR; intended ball diameter; style or model number; and manufacturers ID.
Balls must be permanently marked with the following: intended ball diameter; and SAE classification and trailer GVWR.
Two safety chains are required, one on each side, with minimal slack, and crossed under the tongue. They cannot be secured with the same fastener as the ball.
Each individual safety chain (two required) and attachment must meet a minimum breaking force: Class 1, 2000 lbs; Class 2, 3500 lbs, Class 3, 5000 lbs; and Class 4, equal to GVWR. ♦