Trailer Chains - To Cross of Not to Cross - That is the Question

On Saturday, May 3, 2014 7:14:14 PM UTC-4, JohnDeRosa wrote:

My mate was in the lead and told me later that in his rear view mirror the trailer was seen repeatedly going to the left and right of my truck - basically it kept trying to change lanes - and cars dodging my trailer to get out of the way.

Gotta tow my trailer next week, so this topic has got me thinking.

I buy that crossed chains are better, but it strikes me that crossed chains are not symmetrical and that the dismounted trailer will probably not track stable and straight (as John recounts).

I wonder if it might work better to join the left and right chains with a perpendicular link under the hitch to achieve symmetry? Picture an H-shape chain arrangement.

I think I will experiment and see how my trailer tows/drags on just the chains (slowly and in a parking lot).

son_of_flubber wrote, On 5/3/2014 8:18 PM:
On Saturday, May 3, 2014 7:14:14 PM UTC-4, JohnDeRosa wrote:

My mate was in the lead and told me later that in his rear view
mirror the trailer was seen repeatedly going to the left and right
of my truck - basically it kept trying to change lanes - and cars
dodging my trailer to get out of the way.

Gotta tow my trailer next week, so this topic has got me thinking.

I buy that crossed chains are better, but it strikes me that crossed
chains are not symmetrical and that the dismounted trailer will
probably not track stable and straight (as John recounts).

I wonder if it might work better to join the left and right chains
with a perpendicular link under the hitch to achieve symmetry?
Picture an H-shape chain arrangement.

I think I will experiment and see how my trailer tows/drags on just
the chains (slowly and in a parking lot).

I doubt that would make any difference. The huge problem is the trailer
is no longer connected to the ball, and it's the ball that constrains
the tongue so following directly behind the tow vehicle. With the tongue
free to move side to side and steer the trailer, the dynamics are very
different. My guess: cross the chains, and shorten them as much as possible.

Even better, also do this: every time you hook up, carefully check the
ball and it's attachment, check the coupler for proper functioning, and
connect the chains and lights. And then double-check.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

At 08:48 03 May 2014, Z Goudie wrote:
At 04:14 03 May 2014, BobW wrote:

That said, once when retrieving someone - their vehicle pulling a
factory

PIK-20 trailer - less than two miles from the airport & still in town,
someone
pulled up beside me waving frantically and pointing behind me. I pulled
over
to figure out why. When I pre-flighted the (ready to go [almost!])
trailer,
I
missed catching the fact the rear door wasn't latched. It'd flopped open
and
was skating raucously on the metal brackets that support the door when
the

fuselage rests on it for rigging.

Car and trailer pulled away from traffic lights only to have someone come
up alongside gesticulating wildly.
The trailer door was open and the Dart fuselage was lying on it's side
back
at the lights....

Brennig James on the North Circular (London) in the late 1960's.

I sort of witnessed a similar event on my first ever arrival at Nypsfield
in 1974. I was driving up the hill from Stroud, with my K6e trailer on the
back, when, near the top of the hill, I saw a Kestrel fusilage leaning
against the grass bank by the side of the road. Comp number 29, my friend
John Glossop. I assumed he had arrived a day early for the competition and
landed out on a practice flight. A couple of minutes later I drove in the
airfield gate and saw a trailer in front of me, doors open, no fusilage
inside and John Glossop and a Nypsfield club member (who had noticed the
problem when John stopped to ask directions for parking) walking towards
the back of the trailer. John had apparently thought that the other guy
was pulling his leg, when he gopt to the back of the trailer and found it
open and no fusilage, the expression on his face was one I remeber to this
day. The only damage was a nbroken rudder and Slingsbys got a new one to
him next morning, he was only a bit late launching on the task.

On Friday, May 2, 2014 3:21:47 PM UTC-7, JohnDeRosa wrote:
I have been told that crossing your trailer safety chains is the right thing to do. Something about if the coupler comes off the ball, the trailer will be limited in its wayward travel. Sounds like something for Mythbusters to figure out. Yes or no, what say you?

I don't see how this discussion makes any sense unless it is stated where each end of each chain is attached.

Cobra trailers are delivered to USA with no chains. They only have the standard European emergency brake actuating cable. When I picked up my new glider from the port I took a length of chain. I attached each end of it to each of the bolts that secure the tongue to the trailer floor (redundant attachment to trailer). The front end of the loop is hooked up to one of the tow bar chain eyes with a screw gate link when towing (single point failure). The chain is routed over the top of the trailer jacking wheel attach bracket so it does not drag on the road.

My glider was received shortly after the rash of tow tongue failure reports in USA so I knew the chains had to be attached to the trailer body and not to the tongue itself.

The distance between the trailer axle and the chain attach points is so long on a glider trailer that I doubt it makes any difference to unhook stability exactly where they are attached or whether they are crossed. May be a different story for a short trailer.

Andy

I have exactly the same setup on my 2000 Cobra. What I do is route the chains coming from the eye-hooks on the trailer through the triangular skid on the bottom of the tow bar, then they go on to the hitch eyes. This crosses the chains, and shortens them enough that that don't drag on the road. As with yourself, I have no idea what will happen if the hitch comes off of the ball.

-John, Q3

On Sunday, May 4, 2014 10:12:16 AM UTC-4, Andy wrote:
I don't see how this discussion makes any sense unless it is stated where each end of each chain is attached.

Cobra trailers are delivered to USA with no chains. They only have the standard European emergency brake actuating cable. When I picked up my new glider from the port I took a length of chain. I attached each end of it to each of the bolts that secure the tongue to the trailer floor (redundant attachment to trailer). The front end of the loop is hooked up to one of the tow bar chain eyes with a screw gate link when towing (single point failure). The chain is routed over the top of the trailer jacking wheel attach bracket so it does not drag on the road.

My glider was received shortly after the rash of tow tongue failure reports in USA so I knew the chains had to be attached to the trailer body and not to the tongue itself.

The distance between the trailer axle and the chain attach points is so long on a glider trailer that I doubt it makes any difference to unhook stability exactly where they are attached or whether they are crossed. May be a different story for a short trailer.

Andy

On Sunday, May 4, 2014 10:12:16 AM UTC-4, Andy wrote:

I attached each end of (the chain) to each of the bolts that secure the tongue to the trailer floor (redundant attachment to trailer). The front end of the loop is hooked up to one of the tow bar chain eyes with a screw gate link when towing (single point failure). The chain is routed over the top of the trailer jacking wheel attach bracket so it does not drag on the road.
..
..
..
The distance between the trailer axle and the chain attach points is so long on a glider trailer that I doubt it makes any difference to unhook stability exactly where they are attached or whether they are crossed.

Would it be sound to attach the chain to both the trailer floor AND to the front of the tongue? That way the chains might catch a detached tongue AND be redundant for a failed tongue. It might as well keep a completely detached tongue from becoming a hazard to the following traffic.

Here's a gob-smacking picture of non-tubular failed hitch (not my hitch) http://i50.photobucket.com/albums/f3...r/IMG_1492.jpg

It amazes me that this most simple life-critical structural part would not have a bulletproof safety margin.

Andy wrote, On 5/4/2014 7:12 AM:
On Friday, May 2, 2014 3:21:47 PM UTC-7, JohnDeRosa wrote:
I have been told that crossing your trailer safety chains is the
right thing to do. Something about if the coupler comes off the
ball, the trailer will be limited in its wayward travel. Sounds
like something for Mythbusters to figure out. Yes or no, what say
you?

I don't see how this discussion makes any sense unless it is stated
where each end of each chain is attached.

Cobra trailers are delivered to USA with no chains. They only have
the standard European emergency brake actuating cable. When I picked
up my new glider from the port I took a length of chain. I attached
each end of it to each of the bolts that secure the tongue to the
trailer floor (redundant attachment to trailer). The front end of
the loop is hooked up to one of the tow bar chain eyes with a screw
gate link when towing (single point failure). The chain is routed
over the top of the trailer jacking wheel attach bracket so it does
not drag on the road.

My glider was received shortly after the rash of tow tongue failure
reports in USA so I knew the chains had to be attached to the trailer
body and not to the tongue itself.

The distance between the trailer axle and the chain attach points is
so long on a glider trailer that I doubt it makes any difference to
unhook stability exactly where they are attached or whether they are
crossed. May be a different story for a short trailer.

First, if you think you have a trailer with an inadequate tongue, I
think you should replace it with the correct tongue. Cobra, or perhaps a
dealer, that tell you what tongue your trailer should have. Replacing it
is not hard or expensive.

Second, with the chains connected only to the trailer body, a trailer
that disconnects from the hitch will be far less stable than if the
chains are connected near the coupler.

Third, even if you have the chains connected to the trailer body, you
can have also have the chains connected at the coupler.

There is bolt that holds the coupler to the tongue on my Cobra trailer.
I replaced with with a longer, high strength bolt that captures a chain
link from one chain on the left side, and a link from the other chain on
the right side. I used thick washers between the bolt head (and the bolt
nut on the other side) to help retain the link.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl

On Sunday, May 4, 2014 7:40:31 AM UTC-7, Eric Greenwell wrote:

First, if you think you have a trailer with an inadequate tongue, I

think you should replace it with the correct tongue. Cobra, or perhaps a

dealer, that tell you what tongue your trailer should have. Replacing it

is not hard or expensive.

***I don't think that. The Cobra tongues that failed were round tube. My trailer has the higher load rated square tube tongue.


Second, with the chains connected only to the trailer body, a trailer

that disconnects from the hitch will be far less stable than if the

chains are connected near the coupler.


****Show me the math. The difference in distance from the axle is insignificant. Ontario ministry of transportation says this about chains "Safety chains should be crossed under the tongue to prevent the tongue from dropping to the road should the primary hitch accidentally disconnect." - Nothing to do with trailer stability.

Third, even if you have the chains connected to the trailer body, you

can have also have the chains connected at the coupler.

Agree, but the only reason for going that is to reduce the amount the trailer will overrun the vehicle when stopping after a disconnect. It won't overrun if the trailer emergency brake activates.

That of course leads to a completely different discussion - Why do Americans insist on chains when the trailer designer did not intend them to be used?

What is done in other parts of the world? - Rely on automatic emergency trailer brake only, or use chains with or without the safety brake cable hooked up?

The following appears to apply in UK -

"Unbraked trailers must have a stout secondary coupling, such as a chain, which is connected securely to the towing vehicle when it is being towed. The secondary coupling must be tight enough to prevent the trailer's tow hitch from hitting the ground if the vehicle becomes uncoupled.

Braked trailers must be fitted with hydraulically damped coupling and auto reverse brakes to give braking efficiencies required by EEC Directive 71/320. All wheels must be braked. Braked trailers must be fitted with a breakaway cable. This must be attached to the towing vehicle in such a manner so that, should the trailer become detached, the breakaway cable will operate the trailer's brakes."


Andy

"JohnDeRosa" wrote in message
...
I have been told that crossing your trailer safety chains is the right
thing to do. Something about if the coupler comes off the ball, the
trailer will be limited in its wayward travel. Sounds like something for
Mythbusters to figure out. Yes or no, what say you?

And while you are at it, anyone have a great crazy "trailer came off the
ball" story to share? You first.

- John

The biggest reason to cross is to keep the tension on the chains equal while
turning sharp, especially.

When the chains are not crossed, if you are turning left, the attach points
on the left side of the trailer and the left side of the hitch are both
getting closer to each other. At the same time, the attach points on the
right side are both getting further away from each other. The slack on the
left may allow the chains to drag. The chains on the right have to be left
loose enough that they do not break or bend something from the stretch.

The end result is that the chains must be much less tight if they are not
crossed. They may drag, if not crossed.

When the chains cross, the left hitch attach gets closer to the trailer, but
the right trailer attach gets further away from the hitch. They cancel out.

Plus, the crossing chains do catch the hitch. I was pulling a boat out with
a borrowed vehicle with a wrong size ball, or the hitch was not latched, or
something. It caught the hitch.
--
Jim in NC



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On Sunday, May 4, 2014 7:40:31 AM UTC-7, Eric Greenwell wrote:
Andy wrote, On 5/4/2014 7:12 AM:

My configuration is to have both the trailer chain and the European brake cable attached, with the chain carrying slightly more slack than the cable. This way, should the trailer become disconnected from the hitch on the tow vehicle it will put on the trailer brake before the chain goes taught. I've only had one occasion to test this setup, when crossing railroad tracks. It worked exactly as intended, with the brake preventing the trailer tongue from spearing the towing vehicle.

I only connect a single chain, so nothing to cross, but I also leave the tongue wheel on (tightened), so I don't have the worry of the tongue hitting the pavement.

9B