Where and How to Attach Safety Chains

What are the best ways to attach safety chains on a trailer?  That’s a simple question without a single best answer.  Don’t you hate it when the answer starts with “It depends . . . “?  Unfortunately, it does depend on many other things — like how heavy the trailer is, the construction type, and perhaps most important, your biases and priorities?

That said, there are definitely some things to avoid.  So, let’s look at some bad ideas and learn, then at some good ideas.  Learning good technique by evaluating the bad.  Ah, but First, the goals.

Why Safety Chains?

While this may be a dumb place to start, let’s give a quick nod to why we have them in the first place.  One, because it’s the law.  Two, because it’s part of being responsible when towing.  And Three, to compensate for our own oops’.  Read more in this article on Trailer Safety Chains.

Crash Did Not Have To Be This Bad
Interesting photo.   I don’t know the circumstances, but one safety chain is loose, and the other is much too long.  Look at the distance from hitch to coupler.  This accident did not have to be this bad.

A Fourth, which is (hopefully) an extreme rarity — to save your own life.  Read this post about dangling above death by a single trailer chain.

The point of asking ‘Why Safety Chains?’ is to make sure as we attach them, we don’t thwart the reasons for having them in the first place.  If the reason for having them is to keep the trailer connected in the rare event a hitch disengages, then the attaching must do the job if we need it.  Unfortunately, that is the purpose of the article.  So many chains attach in ways that won’t accomplish the task if you need it.

Now let’s look at some bad ways to attach safety chains on a trailer.

Things To Avoid As You Attach Safety Chains

I did a few searches on Google and YouTube for attaching safety chains, and I am flabbergasted at the things people are teaching.  It’s one thing to put the chains on, and it’s quite another to hold the violent events they are there for.  Please, question what you see and hear — EVEN in this article.  If things are contrary to sound thinking, disregard them.

OK, let’s get on with it.  Let’s learn the GOOD by evaluating BAD.  Here are some examples:

Wimpy, Wimpy, Wimpy

Hopefully this one goes without saying:  Safety chains must be strong.  How strong?  In most places the law says the chain breaking strength must be equal to or exceed gross trailer weight.  That means for a 7,000 lb capacity trailer, each chain must have a break strength greater than 7,000 lbs.  With 2 chains, that’s 14,000 lbs total.

Chain Break

Please Note:  There are 2 strength numbers for chain.  1) Breaking Strength is the minimum load that can break the chain.  2)  Working Load Limit (WLL) is the max safe working load for the chain in continuous service.  WLL applies in situations where the chains hold a load, like binding a load onto your trailer.  Think logging chains.  For safety chains that attach at the hitch, it’s the Breaking Strength we look at.

I see a lot of chains that look pretty wimpy.  I can’t verify such, but swing-set chain is not sufficient.  Also, it doesn’t do much good to have strong safety chain if they attach to something wimpy.  More about that below.

So, our First Rule:  Choose chains that are STRONGER than the total weight capacity of the trailer.  Attach safety chains in ways that are stronger than the chain.  Hooks and connections should all be stronger than the chain too.

From a legal perspective, each jurisdiction is a little different, so make sure you exceed your laws.  Here’s a publication for Trailers in the United States that looks pretty official.

Where’s The Grinder?

Why is this NOT a good way to attach safety chains?

Trailer Safety Chain Connection At The Tongue
Connection Loops are right at the bottom.  If this hitch fails, the chains are first to contact the ground and grind off.

If the tongue of the trailer did come off the hitch, one strong possibility is the tongue would drag the ground.  The event can be violent, and often at speed, so if the tongue does hit the ground, it will immediately start grinding through whatever touches.  So, we don’t want something to hit that will dig in, for sure.  But we also don’t want to grind off the very thing that is keeping the trailer attached.

Second Rule:  Attach safety chains in a way that they won’t grind on the ground if they are needed.  That means attach chains somewhere that’s not under the tongue.

In the photo above, the loops may be good — I don’t know about their strength (see below) — but not in the position shown.

Heat Of The Moment

The next BAD idea is a classic.  It’s so common, and it boggles my mind.  OK, many trailer owners won’t know the difference, and I don’t blame them.  However, the person building the trailer is responsible.  If they know enough to weld, then they should know that welding changes the strength of steel — especially tempered steel like chain.  When strength matters, please don’t weld chain.

Attach Safety Chains By Welding
Links of the chain attach by weld directly to the trailer.  True, they won’t accidently fall off, but welding heat weakens the links.

Steel is not just steel.  There are thousands of steel alloys, each with unique characteristics.  Yet steels change with high heat, rapid cooling, or working (like forging).  Steel is great — some alloys are pliable like a coat hanger, others are hard and tough like a hammer.  While I don’t know the exact alloys for safety chain, I do know the links have temper for high strength and toughness.

Chain Link Weld
It’s a nice weld. Yet, it’s not the weld that’s concerning. It’s the change in material properties, and now this is the weakest link.

While chains are really tough, the heat of welding reduces the strength, and there’s no going back.  Even if you can’t see much difference, the actual metal is now annealed, so it’s weaker.  Maybe it’s still strong enough, or maybe not.

Third Rule:  Don’t weaken the chain while putting it on.  Don’t weld chain, and don’t bend it.

Of course, there are limits.  If the chain is overkill, then maybe it doesn’t matter.  However, if you bought a chain rated for your trailer, why weaken it?  Just consider the situation and don’t make a rookie mistake.

How Long?

How long should safety chains be?  Long enough that things won’t bind when turning.  Actually, that’s not very long.

Trailer Hitch Chains That Are Too Long
An example of Trailer Safety Chains that are too long.

Extra length does 2 things:  1) In emergency situations, short chains make it easier to control.  2)  Momentum in motion allowed by long chains creates a bigger impact when a chain comes tight.

Long chains allow the trailer more freedom to yank back and forth, forward and back.  The tongue can dive under the car, or slam in the back (like the photo above).  It means more damage, and harder to control with violent movement and impact each time the chains come tight.  If the safety chains attach (on the trailer and on the tow vehicle) close to the hitch, the chains can be quite short.  That’s best.  Please read the follow-up article about how to shorten chains.

The hiccup comes with the need to accommodate multiple tow vehicles, and the solution is adjustable length.  (Which is one more reason to NOT weld chain directly.)

Fourth Rule:  Make the chains as short as practical, and if possible, attach safety chains in a way that allows length adjustment.  If that’s not possible, use other ‘appropriate’ ways to effectively shorten the chain.

Awkward!

While cables are a reasonable substitute for chains, they have one very important similarity.  Chains and cables only work in tension.  It’s super hard to “push” a chain, and they don’t have much strength if you “kink” them.  By their very nature, chains and cables bend easily, but they are strongest when dead straight.

Look at this photo and see if you can find 2 things wrong?  (There’s more than 2.)

Trailer Safety Cables

What’s Wrong in the photo?  1.  Hopefully you see the connection point on the tongue that will grind when it hits the ground.  2.  The cable connection is 90° from expected forces, so cables will immediately “kink” if violent force is applied.  A “kink” seriously weakens a cable, and you can say the same for bent chain links.  3.  The bracket for attachment is weaker than the cables.  4.  The cables are much too long.

Fifth Rule:  Think about the direction of forces.  If chains are violently thrust into action, make sure things holding those forces are directionally correct.

Another Bad Idea

In the category of “Bad Ideas” we’d be remiss if we didn’t also point out the problems with twisting safety chains.  We’ve covered that already in this Article on Twisting Safety Chains.


Now The Good Ways To Attach Safety Chains

We’ve learned from some mistakes above, now it’s time to look at some much better ways to attach safety chains.

Bolt Through

Bolting for chains is a mixed bag.  If you support the link and the forces properly, it’s great.  If you crush the chain, use a wimpy bolt, or bolt to a wimpy member, then it’s bad.

Here’s an application I like for my trailer.  The tongue is 3/16″ thick, and the chain allows a 7/16″ diameter bolt.  Using grade 8 bolts with Nylock nuts and a bunch of modified washers, the attachment is tough.

Attach Safety Chain With Bolts

The 2 through bolts make the chain length easy to adjust.  My chain loops under rather than being cut, but the portion under does nothing.  You can also see the breakaway pin switch on the one side just above the chain.

Does it follow the rules?  1)  Choose chains that are strong enough.  2)  It won’t grind chains on the ground.  3)  It doesn’t weaken the chain, and the mounting (grade 8 bolts of of max diameter) is stronger than the chain.  4)  It’s easily adjustable, so chains can be short.  5)  Direction of forces are in line with the chain.  (I will note, however, if the tongue dives under the vehicle, the pull is backward.)  Conclusion:  This one works.

Here’s a one bolt version of the above method.

Attach Safety Chain With One Bolt

Bolt Tabs

Special tabs made to attach safety chains are a great solution.  The tabs are very thick, and have a lot of surface area for welding to the tongue tubes.  One hole allows a link sit against the tab for secure bolting.  Again, grade 8 bolts (in the biggest size that will go through the link).

Simple Bolt Tabs

The one drawback, these don’t allow easy adjustment.  However, if you don’t need adjustability, they’re fine.  You can also easily switch for longer or shorter sections of chain as needed.

Does it follow the rules?  1)  It won’t grind chains on the ground.  2)  It doesn’t weaken the chain, and the mounting (heavy steel tab with grade 8 bolts) is stronger than the chain.  3)  It does not adjust, so chain length will have to be set carefully.  4)  Direction of forces are in line with the chain.  Conclusion:  Overall it does the job well.

Double Tab Bolting

Finally, a double tab with a pin or bolt.  This is a little more complicated to visualize, but it’s 2 flat pieces of metal with the chain between.  We attach the safety chain with a pin or bolt, and the tabs are far enough apart that the chain moves easily for quick re-adjustment.

Double Tab Adjustment to Attach Safety Chain

Does it follow the rules?  1)  It won’t grind chains on the ground.  2)  It doesn’t weaken the chain.  Mounting (with grade 8 bolts and double steel tabs) is stronger than the chain.  3)  It’s easily adjustable, so chains can be short.  4)  Direction of forces are in line with the chain.  Conclusion:  This is a robust design.

If you like this design, but want something configured, try Link Lock.  Their product is similar in concept, but probably better in function.  (Note:  I really like their concept, but I have not been able to get a return call from them.  I spoke to someone a few times, but not the person who can answer technical questions.  Multiple promises to call back did not materialize.  Now the website looks like it’s unattended, so maybe they are not viable?  Let me know if you find out something.  I’d love to buy a set and try them.)

Another Pinned Product

Simple Way To Attach Safety ChainsAlong similar lines as above, here is a product made to pin the chain.  It’s not amazing, but it is available to purchase.  Do a search.  I found some similar at a few places online.  Since I don’t personally know the places, I won’t make a recommendation.

Does it follow the rules?  1)  If it mounts on the side of the tongue, then it won’t grind chains on the ground.  2)  It doesn’t weaken the chain, and the mounting is solid when welded as intended.  3)  It does not allow on-the-fly adjustment, but you can certainly change chains easily for the right length.  4)  Direction of forces can easily align with the chain.  Conclusion:  I think it looks good.  You’ll just need to find the right size for the chain you wish to use.

More Good Ways

The above are a few good ways to attach safety chains, but this list is not exhaustive by any means.  There are a lot of great ways — just ask yourself:

Does it follow the rules?


Now The Test !!

The other day I stopped in at a local trailer lot to see some new trailers they just got in.  I was also looking for some ideas for security, but we’ll cover that in another article sometime.

New Chain LoopHere is what I found on the front of a 14K trailer.  Yes, there are several things in this shot, but for this article, let’s focus on how the safety chains attach.

The Test

In context of the rules above, what do you see?

Just to take a little space, here’s another photo of the underside where the safety chains attach.  It is the same on both sides.

I have to say, for security, the keys do come in really handy!

For this test question, what did you come up with?

Do you need a little more time to think about it?

OK, time’s up.  Time to look at the answers.

 

Safety Chains Wimpy Attach

Answers to Attach Chains For Safety

Here’s what I see:

  1. To Rule 1 – The chains look beefy, and the hooks appear as a good size for the trailer.  Pass.
  2. To the other part of Rule 1 – This loop is NOT stronger than the chain.  It’s the same diameter material, but it’s soft, and it’s welded — the front bit not by much.  This is the weak point.  FAIL.
  3. To Rule 2 – They attach the safety chains to the bottom of the beam.  We could argue that the hitch extends below so the chains would not grind, and I’ll accept that.  The jack will rip right off, but the hitch is very tough.  Pass.
  4. To Rule 3 – Mixed bag.  They did not weld the chain, so that’s good.  Pass.  However, as noted above, the loop is the same diameter, and because it’s on the chain it is effectively a link.  If you’re going to weld it on with a loop or some other piece, make sure it is bigger so when it’s weakened by welding, it will be at least as strong as the chain.  Overall, FAIL.
  5. To Rule 4, we don’t know without a tow vehicle.  I will say, however, that the attach point is close to the hitch, so that’s good.  Pass.  They look long to fit most anything, but we won’t knock that since we don’t really know.
  6. Unofficially, with Rule 4 it is not hard to make the chains adjustable so the customer doesn’t have to come up with something else.  That’s a Fail from a customer service standpoint.
  7. To Rule 5, the force direction is generally correct.  Pass.

Did you see all that?  Excellent, you’re ready to be an expert.  Do you see something else I missed?  Leave a comment.

Thank You For Considering How To Attach Safety Chains

We welcome comments below.  If you know of a good way to attach safety chains, send a quick blurb from our Customer Submission page.  Send a photo too, if you can.

There’s really no reason to compromise with safety chains.

See the Tips Library for more articles, like this one about Good Ways To Shorten A Chain.  Also, try the new “Show Me” search field at the top of the page.  Just type in a question and we’ll show you what we have.

3 thoughts about “Where and How to Attach Safety Chains”

  1. About selecting a location for safety chain. The trailer selected was not described by the structure material. Was it aluminum or steel? The article was pretty clear about where not to begin placing chains. Mine, purchased from a well known trailer manufacturer in Indiana, came with a chain hanging under the tongue and clearly fighting for space with the flat four wires.

    I removed the front bolt from the coupler and the chain dropped.

    I like the idea of bolting the safety chain to the side of the 1/4” thick aluminum box that is the tongue and supports the coupler. So, it is a 2K torsion axle.

    So, can I use the aluminum tongue to bolt the chain to. Also my bolts are 1/2” diameter and marked “BY”. Is that equivalent to grade eight? Those 1/2” bolts easily fit into the chain and could be bolted to the tongue. But there needs to be either spacers or washers of various diameter to give clearance to the 90 degree link on each side. Is there a good reason to use 7/16” bolt vs 1/2”? If yes 7/16” parts cost less!

    Reply
    • Please see the Bolts 101 article for info on the bolt markings. If BY is the only marking, then it’s probably Grade 2-ish. For bolts in aluminum, the bigger the better for surface areas. 1/2″ sounds fine, but that is your judgement. Yes, spacers are required – I sometimes use a nut from a bolt size larger as a spacer. Depends if you are attaching between links or at the chain end. Don’t be afraid to grind something to fit.

      Reply
  2. Great article. I’ve been thinking my safety chains weren’t connected that well, and just figured they were meant to break away. I decided to beef up the chains, and read this article and now realize the current chin connection is woefully inadequate. I and my boat thank you for the information..

    Reply

3 thoughts about “Where and How to Attach Safety Chains”

  1. About selecting a location for safety chain. The trailer selected was not described by the structure material. Was it aluminum or steel? The article was pretty clear about where not to begin placing chains. Mine, purchased from a well known trailer manufacturer in Indiana, came with a chain hanging under the tongue and clearly fighting for space with the flat four wires.

    I removed the front bolt from the coupler and the chain dropped.

    I like the idea of bolting the safety chain to the side of the 1/4” thick aluminum box that is the tongue and supports the coupler. So, it is a 2K torsion axle.

    So, can I use the aluminum tongue to bolt the chain to. Also my bolts are 1/2” diameter and marked “BY”. Is that equivalent to grade eight? Those 1/2” bolts easily fit into the chain and could be bolted to the tongue. But there needs to be either spacers or washers of various diameter to give clearance to the 90 degree link on each side. Is there a good reason to use 7/16” bolt vs 1/2”? If yes 7/16” parts cost less!

    Reply
    • Please see the Bolts 101 article for info on the bolt markings. If BY is the only marking, then it’s probably Grade 2-ish. For bolts in aluminum, the bigger the better for surface areas. 1/2″ sounds fine, but that is your judgement. Yes, spacers are required – I sometimes use a nut from a bolt size larger as a spacer. Depends if you are attaching between links or at the chain end. Don’t be afraid to grind something to fit.

      Reply
  2. Great article. I’ve been thinking my safety chains weren’t connected that well, and just figured they were meant to break away. I decided to beef up the chains, and read this article and now realize the current chin connection is woefully inadequate. I and my boat thank you for the information..

    Reply

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