Author Topic: Bent Coupler on 21RBS  (Read 10198 times)

charliem

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Bent Coupler on 21RBS
« on: October 24, 2014, 03:59:35 PM »
[font size="3"]Iím seeing this coupler deformation on a 21RBS. Apparently the tongue weight of 2 gas bottles and 2 batteries plus the action of the WDH and the dynamic loading of travel and roadway dips is too much for the coupler as installed.

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This is the second time Iíve dealt with this problem. The first time I assumed the WDH was over compensating and putting too much torque on the ball/coupler. I ordered a new coupler from LL and it arrived with no bolt holes drilled. Apparently the coupler is designed only to be welded to a steel frame, not bolted as from LL. I drilled the new holes, reinstalled with the original bolts, and  lightened the WDH load to a minimum for the required effect. Same problem returned after a few trips.

Iím thinking the fix might be to straighten the coupler and add a bolt to each side, drilling through the steel coupler and through the outer wall of each side A frame member in the approximate area indicated by the red circle. The inner walls of each frame member are inaccessible due to welded plates. Short 1/2" SS hex bolts with flat washers and locking nuts might work.  Maybe two 3/8Ē bolts stacked vertically on each side?

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The bolts and aluminum frame walls would be in almost perfect shear load and close to the vertical center of the frame members, and there is not much bending stress on the frame at this point, so degradation of frame strength should not be an issue. I also don't think not being able to go completely through the frame member is a problem, again due to the primary shear load. Other solutions might be pieces of thick steel flat stock spanning the two bolts on each side and extending forward of the front bolt: in effect a much larger washer. Donít like this one as much.

Techie, Dave, Doug, LL, others: Jump in here with you comments and ideas. I donít think this is a potential failure mechanism, but it does put unusual wear on the ball/coupler combo and just looks wrong. What say? [/font]
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Charlie
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daplumbr

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Bent Coupler on 21RBS
« Reply #1 on: October 24, 2014, 04:19:29 PM »
A couple of things come to mind. Is it possible to get a heavier duty coupler to bolt on there? On my 16TBS, the coupler covers the entire frame of the trailer top to bottom. Perhaps the 21 foot trailer has a deeper frame, but in any event, that coupler looks pretty small and I wonder if it's too light for the stresses? I like the single 1/2 inch SS bolt in the side as the best solution for the coupler you have. And use a heavy grade bolt. You might consider replacing the existing bolts too, give the deformation there's been a lot of stress on them too. 

david

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Bent Coupler on 21RBS
« Reply #2 on: October 24, 2014, 04:39:43 PM »
[p]As you point out, that coupler was never designed to be used that way. Simply bolting through the top, puts all the stress where the bend is, duh!

Put two bolts in horizontally on each side, one where your circle is and another about three inches back where the angle is. That will essentially do what welding does on a steel frame and distribute the stress down to the frame.

LL makes some compromises to use steel components with their aluminum frame, and this is one that they blew. I will have to look at my 16TBS to see if the coupler is similar and maybe do the same. It hasn't bent.....yet.[/p][p]
[/p][p]And don't straighten it. Get LL to send you one more new one. It is their problem.

David[/p]
David M

16TBS towed with a 2013 Nissan Pathfinder

charliem

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Bent Coupler on 21RBS
« Reply #3 on: October 24, 2014, 04:44:00 PM »
[quote timestamp="1414178369" author="@sandroad" source="/post/4400/thread"]On my 16TBS, the coupler covers the entire frame of the trailer top to bottom. Perhaps the 21 foot trailer has a deeper frame, but in any event, that coupler looks pretty small and I wonder if it's too light for the stresses?
[/quote][font size="3"]Merlin,

That's an interesting observation. My frame is 4" top to bottom and the coupler is only 3" What are yours and what year is your 16?
[/font]
Any 20 minute job can be stretched
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Charlie
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solds88

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Bent Coupler on 21RBS
« Reply #4 on: October 24, 2014, 04:45:07 PM »
Wow, all I can say is "scary". My engineering background makes me think bad application, of course hind sight is always perfect. You could try a heavier duty coupler, maybe move up to a 2 5/16 ball? The other fix that comes to mind, as Merlin suggested, is purchase or design an encapsulated hitch. Regardless of what you decide, I personally would not replace it with the same brand. I've got the 21RBS and I'm going to be watching mine like a hawk. [a href="http://www.etrailer.com/Trailer-Coupler/Bulldog/BD43805W0317.html"]http://www.etrailer.com/Trailer-Coupler/Bulldog/BD43805W0317.html[/a]     

leslie

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Bent Coupler on 21RBS
« Reply #5 on: October 24, 2014, 04:46:05 PM »
I am going to keep an eye on my coupler after reading this post. I have a 21-BHS, and I have 2 gas containers and 2 6 - volt AGM batteries, which weigh even more than lead acid batteries. In any event, the coupler supplied with our trailers should be up to the task, given how much tongue weight is needed if we were to load these things to the max of 5,000 lbs. A minimum of 600 lbs if loaded to the max.
Located in Kentucky and Florida at present

daplumbr

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Bent Coupler on 21RBS
« Reply #6 on: October 24, 2014, 05:17:02 PM »
The frame on the 16TBS is 3 inches deep, so it must be the same 3 inch coupler is used on the 16 and the 21. It looks like LL should be using a heavier coupler on the heavier trailer?

leslie

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Bent Coupler on 21RBS
« Reply #7 on: October 24, 2014, 05:25:43 PM »
Charliem, is yours a 2015 Camplite? I noticed that LL raised the tongue weight from what was listed for the 2014 year. There is an explanation there about the design, axle location and loading that wasn't on LL website for the 2014 models.
Located in Kentucky and Florida at present

leslie

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« Reply #8 on: October 24, 2014, 05:28:22 PM »
Merlin, GVWR for 16 foot models and 21 foot models is the same - 5,000 lbs.
Located in Kentucky and Florida at present

drdave

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« Reply #9 on: October 24, 2014, 09:54:22 PM »
[quote source="/post/4398/thread" timestamp="1414177175" author="@charliem"][font size="3"]

Iím thinking the fix might be to straighten the coupler and add a bolt to each side, drilling through the steel coupler and through the outer wall of each side A frame member in the approximate area indicated by the red circle. The inner walls of each frame member are inaccessible due to welded plates. Short 1/2" SS hex bolts with flat washers and locking nuts might work.  Maybe two 3/8Ē bolts stacked vertically on each side?


[/font]
[/quote]One of the first things I noticed about the coupler on my 2013 16db was the "made in china" stamp.   I'm not sure if that is the industry standard these days, but when it comes to automotive anything I don't trust "made in china" anything...don't get me started on chinese tires.    I think the simplist solution is upgrade to a "made in USA" coupler with a higher wieght rating and/or your side bolt idea.     In lou of drilling into the aluminum I wonder if you can get a local fab shop box out the coupler so it surrounds the A frame, then bolt from the top, sides and/or bottom.  


charliem

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Bent Coupler on 21RBS
« Reply #10 on: October 24, 2014, 10:00:17 PM »
[quote timestamp="1414182343" author="@leslie" source="/post/4406/thread"]Charliem, is yours a 2015 Camplite? I noticed that LL raised the tongue weight from what was listed for the 2014 year. There is an explanation there about the design, axle location and loading that wasn't on LL website for the 2014 models.[/quote][font size="3"]Thanks for the tip on the LL website. I never did believe the 250# number and I don't think anyone else did either. I think LL is just catching their publication up to reality. My 2014 model's TW is 525# fully loaded including 2 bikes on the rear and empty tanks. [/font]
Any 20 minute job can be stretched
to a week with proper planning

Charlie
NW Florida

charliem

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Bent Coupler on 21RBS
« Reply #11 on: October 24, 2014, 10:17:03 PM »
[quote source="/post/4411/thread" timestamp="1414198462" author="@tlbones"]One of the first things I noticed about the coupler on my 2013 16db was the "made in china" stamp.   I'm not sure if that is the industry standard these days, but when it comes to automotive anything I don't trust "made in china" anything...don't get me started on chinese tires.    I think the simplist solution is upgrade to a "made in USA" coupler with a higher wieght rating and/or your side bolt idea.     In lou of drilling into the aluminum I wonder if you can get a local fab shop box out the coupler so it surrounds the A frame, then bolt from the top, sides and/or bottom.  

[/quote][font size="3"]I agree on the China thing, but I don't think that's the problem here. It's simply misapplied and misinstalled. The coupler was designed to be welded all around to a steel A frame. I don't think you can weld two dissimilar metals due to differing melting temperatures. I've not found any coupler with higher ratings that did not also require
 welding. You just can't hold these kinds of loads by bolting from the
top. I'm going to try the added bolt fix first. I've thought of the welded box idea, but that's a bit harder to do.
[/font]
Any 20 minute job can be stretched
to a week with proper planning

Charlie
NW Florida

drdave

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Bent Coupler on 21RBS
« Reply #12 on: October 24, 2014, 10:34:56 PM »
[quote source="/post/4413/thread" timestamp="1414199823" author="@charliem"][quote source="/post/4411/thread" timestamp="1414198462" author="@tlbones"]One of the first things I noticed about the coupler on my 2013 16db was the "made in china" stamp.   I'm not sure if that is the industry standard these days, but when it comes to automotive anything I don't trust "made in china" anything...don't get me started on chinese tires.    I think the simplist solution is upgrade to a "made in USA" coupler with a higher wieght rating and/or your side bolt idea.     In lou of drilling into the aluminum I wonder if you can get a local fab shop box out the coupler so it surrounds the A frame, then bolt from the top, sides and/or bottom.  

[/quote][font size="3"]I agree on the China thing, but I don't think that's the problem here. It's simply misapplied and misinstalled. The coupler was designed to be welded all around to a steel A frame. I don't think you can weld two dissimilar metals due to differing melting temperatures. I've not found any coupler with higher ratings that did not also require
 welding. You just can't hold these kinds of loads by bolting from the
top. I'm going to try the added bolt fix first. I've thought of the welded box idea, but that's a bit harder to do.
[/font][/quote]I understand it's more work to box out the frame than bolt.    I don't think you need to fully box it the entire lengh....I think more of a strap around the leading edge of the a frame concept perhaps bolted on with the side bolts you propose instead of welding?    Maybe if you can find a U clamp large enough to strap around the coupler/A frame?  Best of luck and I am troubled by your discovery.   I see you posted in the factory section.   I really hope they respond with some help.   This shouldn't be your problem to solve alone.

charliem

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Bent Coupler on 21RBS
« Reply #13 on: October 24, 2014, 10:49:26 PM »
[quote source="/post/4415/thread" timestamp="1414200896" author="@tlbones"]Maybe if you can find a U clamp large enough to strap around the coupler/A frame?
[/quote][font size="3"]Funny you should say that. The U-bolt was my first thought and it might work. I just don't know where to find that large galvanized U-bolt.
[/font]
Any 20 minute job can be stretched
to a week with proper planning

Charlie
NW Florida

solds88

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Bent Coupler on 21RBS
« Reply #14 on: October 25, 2014, 02:39:19 AM »
[font face="comic sans ms" size="3"]Here is a 15K bolt on coupler for a 2 5/16 ball. [a href="http://www.etrailer.com/p-BD44150WH301.html"]http://www.etrailer.com/p-BD44150WH301.html[/a] [/font]