By Dave Solberg
There have been several discussions on proper connection of trailer safety chains. An article regarding the connection of the safety chains to a hitch that broke off prompted several comments worth addressing.
I think we all agree that safety chains are a good thing whether you are driving a motorhome and pulling a towed vehicle (“toad”) or have a truck towing a trailer. They help with runaway trailers, help maintain control, and are most often required by state road use laws.
The confusion is, do the chains need to be crossed, can you twist the chains to shorten them, and how should the clevis hook be connected? I grew up towing manure spreaders with an old Allis Chalmers or Oliver tractor and never knew what a clevis hook was until just recently!
What is a clevis hook?
There are many different types of hooks that can be used for towing applications, but the clevis hook seems to be one of the most common for larger or heavier safety chains. It features a distinctive design characterized by a clevis, a U-shaped metal bracket with a pin or bolt running through its ends. The hook itself is attached to one end of the clevis, and the other end typically connects to a chain, cable, or other lifting equipment.
From what I have found, the “clevis” description is not actually the hook, but the U-shaped connection or fastener.
There are two types of hooks that feature the clevis fastener: an open-faced version and one with a spring-loaded safety latch commonly called a “keeper” or snap lock. The “keeper” is a metal latch that is designed to keep the hook from bouncing out of the hitch connection during travel.
Should the chains be crossed underneath?
It is highly recommended to cross the chains underneath to create a cradle if the trailer hitch detaches from the ball and drops down. Some states have road use laws that state there must be a cradle or support mechanism for the trailer tongue; however, here is where the confusion starts.
Most states do not publish their road use laws or they change them almost annually. Thus, you will find a constant misinterpretation at all levels, from the local DOT office, highway patrol officers, and DOT officers. In my opinion, it is a good idea to cross the chains, make sure they do not drag on the ground, and are long enough to allow the trailer to turn in tight situations such as campgrounds or parking lots.
Should the hook be installed from the top or the bottom?
This is where there is quite a bit of conversation and nothing in the actual road use laws that I have found. Plus, you can find “experts” that state both ways. I have always been told by towing experts to connect the hook from the bottom with the opening facing the trailer.
The debate is whether the hook will “bounce” going down the highway and come off, since there is limited tension on the chain. I do believe a spring-loaded safety latch will prevent anything from jumping off the hitch.
Can you twist the chains to shorten them?
This is one of the issues I received a ton of comments for, as I was “old school” and we did this all the time. However, I did not have an emergency situation that tested the chains that were twisted, so I had no factual data.
Many stated that it derated the weight capacity; however, I have found that anyone can say anything on the internet without any data to back it up. And, unfortunately, if it’s written, many people just believe it. However, I did find data in “An Engineering Guide For Trailer Safety Chain Installation, Attachment and Use” published by Alpine Engineering & Design, Inc.
Here are some excerpts from the report
Auxiliary safety connections for trailers were introduced as early as 1939 as described in US Patents 2,225,130 and 2,196,115 and the configuration where two chains are crossed under the coupler, which has become the standard auxiliary connection, was seemingly introduced as early as 1959. The purpose for the auxiliary safety connections as stated in the patents is “to hold the trailer connected with the machine and on the road in case of injury to the usual hitch or loss of a coupling pin or the like (2,225,130 Patent).
Twisting chains is a commonly recommended solution to chains that are too long. However, this also has significant drawbacks. First, most chain manufacturers say not to twist the chains because the load ratings only apply to longitudinal force. Again, the SAE684 standard states that nothing should be done to the chain that reduces its strength. Further, testing done by Alpine Engineering & Design, Inc. shows that twisting safety chains can reduce their strength by as much as 75%. To put that into perspective, a chain rated to 10,000 lbs. would only be able to hold 2,500 lbs. Further, a small amount of force can cause the twisted chain to lengthen significantly. This can also lead to the tongue contacting the road. Twisting trailer chains is not recommended as a safe solution to trailer chains with excess length.
Do not twist the chain
So, there is an actual test and proof not to twist the chain, but rather remove links or use Link Lock™, which they have developed and tested.
They also have state road use laws pertaining to safety chains available here.
Here’s more info from Federal Motor Carrier Safety Administration, DOT.
Conclusion
As you can see, finding documented data on road use laws can be a very difficult task. Therefore, in my opinion, it is best to err on the side of safety. And, as always, I’m still learning!
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Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
RVDT2759
You can go to most hardware stores and buy Grade 70 chain cut to length thus avoiding the need for devices like Link Lock, zip ties, tongue wrapping or twisting. Or you can purchase a die grinder and cut-off wheel and cut to fit yourself.
Don’t forget the attachment points. My forest river TT had a single piece of soft rebar holding both certified chains to the trailer with a cheesy weld. No way it would have held!!!
My 28 foot toy hauler has the same ‘cheap’ attachment point.
Where is the RVIA? They claim to be a watchdog about safety in the RV industry.
There is no way that small loop of steel would hold.
I have observed on many trailers in recent years that the safety chains are attached to a single point under the tongue making it impossible to cross them.
And while on the subject of safety chains, how many people use them on their vehicles being transported by tow dolly? When I purchased my used tow dolly it did not have safety chains. I promptly purchased them. I have observed a few dollys in the campgrounds.without safety chains for vehicle securement.
Aaron
Yes. Many trailers, especially smaller sizes, now come with a single attachment point behind and below the coupler. Crossing the chain is wholly ineffective. I am sure it is a cost savings for the frame manufacturer.
Virtually EVERY problem you see with RVs is a result of manufacturers trying to “Save” money…… Build cheaper.
I have dexter axle 3500#. I put new brake assemble and new hub assemble on all 4. They are self adjusters. I have one wheel that is running hot. I’m lost as to why?