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Friday · 06-06-2012, 10:37 PM

But the pawl takes a pounding anyway every time the trailer decelerates... every bump... with a constant force on it, and it pivoting WITH the coupler... it might work even better?

I can't be much more load than already designed... these couplers are used on 8,000lb trailers...

TG Twinkie · 06-07-2012, 06:18 AM

Is there a reason that RV manufacturers use the pawl type couplers? Seems like the Bull Dog would be a perfect fit. No pawl at all.

SteveH · 06-07-2012, 06:57 AM

I keep reading there is no movement between the coupler and the ball, but in my mind that is not correct.

Granted, there is no movement from the act of turning the rig because the ball turns with the trailer, but there is still movement when the road is irregular and the tow vehicle rolls one way, and the trailer the other. Also there is movement in the vertical plane when the rig goes thru a dip in the road, or over a hump in the road.

I know these movements are not a great as the movement from the act of turning, but there is still movement. If there wasn't, you wouldn't need a ball coupler.

I agree with TG Twinkie...the Bull Dog coupler would be perfect for this hitch system, and I have actually looked at replacing my coupler because I believe the coupler on an Airstream is the weak link in the system, but I noticed the Bull Dog is longer out the front than the coupler the Airstream is originally equipped with, and wonder if there is enough room to move the parts on the "A" frame that far foward, both with this hitch, and my existing ProPride.

So, while the Bull Dog is stronger at the actual coupling, is it as strong between the coupler and the "A" frame because of the extra length?

M2HB · 06-07-2012, 07:26 AM

Quote:

Originally Posted by Friday

But the pawl takes a pounding anyway every time the trailer decelerates... every bump... with a constant force on it, and it pivoting WITH the coupler... it might work even better?

I can't be much more load than already designed... these couplers are used on 8,000lb trailers...

Keep in mind, many couplers aren't built as strong for the rearward forces. If a trailer is set up properly, there isn't much force rearward if the brakes are adjusted properly. Some couplers have a small weld holding the mechanism in the coupler. A short vertical chain with a bar across the top of the tongue would change the direction of the force from rearward to upward, into the top of the coupler where the force was designed to be applied.
If I was Andersen, I would be concerned about liability if their WD hitch causes some couplers to break. The fix seems simple enough.

TG Twinkie · 06-07-2012, 07:46 AM

I would assume that the rating on the Bull Dog takes into consideration the extra length just as the extra length on a ball mount (stinger) is calculated into the rating. With the Andersen setup. Wouldn't it be a matter of chain length to enable the brackets to be located in their original location?

purman · 06-07-2012, 07:52 AM

Quote:

Originally Posted by M2HB

That could be a problem since the force is against the rear of the coupler instead of the front, where the force was designed to be placed. The torsion bars put the force downward on the top of the ball where weight was designed to be. I think this is a serious problem with the Andersen design.

This is a misconception. A WD doesn't put down pressure on the ball, the weight of the trailer does that. If the WD did that it would just push the front end in the air more and you want it down not up.

What the WD does is pull the bottom of you hitch towards the trailer as you pull up on the end of the torsion bars. it then transfers that pressure through the receiver and frame to force the front of you TV down.

Watch this video it explains it all:

Andersen Weight Distribution Hitch vs Spring Bar Weight Distribution -comparison - YouTube

Also a regular WD puts a lot of down force on your trailer frame

bad. this is virtical presure. The Andersen puts it laterally

good. less stress on the trailer frame.

The pressures are exactly the same, the Pawl gets no more pressure or force put on it than it would with a regular WD because the forces put on the hitch are the same. Plus as Friday says; stopping is going to put more force on the pawl than anything.

but even better; with a regular WD you have set weight bars, with the Andersen you can dial in any weight.

sure the coupler will move slightly on the ball but not much. They are talking side to side motion of a regular hitch. and the wear from the sway control would probably be the same as the wear on you ball and hitch. not much. I'm sure you would have to put a ton of miles before that brake sleeve starts to wear. Parts wear out on other WD's all the time.

This system puts the same pressure on the same parts as a regular WD but does it in a more efficient way with less parts, and is easier to put on and off.

I see no drawbacks what so ever. Plus my kids won't get grease on them and I won't have to lug a heavy hitch in and out of my receiver when I get to camp.

I believe HowieE is right, this is a game changer..

M2HB · 06-07-2012, 08:13 AM

You are correct, a regular WD does put a downward force on the frame. The Anderson puts a rearward force on the frame. Both forces are transferred forward (creating the WD) by these forces. You are saying that a regular WD hitch doesn't put more force on the hitch. If that is the case, how does it transfer the load? If it didn't put more force on the hitch than the Andersen doesn't put more force on it either. They both put more force on the hitches, just in a different direction. I like the Anderson setup, but I question the force being put on a coupler in a rearward direction, against the locking mechanism that may not have been designed for that force. Anderson's concept it great, but I would prefer to force against the top of the coupler and not the back.
As far as a downward force on the frame, if the frame won't take that force than it was not designed correctly for the weight being used on that frame. I have built many equipment trailer since the mid 1970s and your point is well taken. Many trailers, RVs especially, are not made with proper frames for the load that they are expected to be carried by the owners. Take for example, an expensive single axle AS trailer, with a 4,500# axle and a 3" structural channel frame. I would never consider making a 4,500 #, single axle equipment trailer that is almost 20' long, with 3" channel. I would use 4" channel, or maybe even 5" channel with a 5,200 # axle. The weight difference is only about 150 # and the increased hauling capacity is around 550 # with no structural issues to worry about.

SteveH · 06-07-2012, 08:14 AM

Quote:

Originally Posted by TG Twinkie

Wouldn't it be a matter of chain length to enable the brackets to be located in their original location?

Yes, assuming you only wanted to use the Andersen WD hitch with the coupler. Any other type of WD system that used bars might be a problem because it would move the snapups, and any other hardware such as the cams and their mounts in the case of a Reese, towards the front, and these systems have all been designed for the average length bars/couplers.

purman · 06-07-2012, 08:25 AM

Quote:

Originally Posted by M2HB

You are saying that a regular WD hitch doesn't put more force on the hitch. If that is the case, how does it transfer the load? If it didn't put more force on the hitch than the Andersen doesn't put more force on it either. They both put more force on the hitches, just in a different direction.

Sorry I will clarify: yes they both put forces on the hitch to distribute the weight. What I am saying is the Andersen puts the weight and pressure in the exact same place as a regular WD does. It doesn't put it in a different direction at all. Watch the video. It may seem like it does by the design but a torsion bar pulls on the bottom of the hitch just like the chains for the Andersen do.

your just not pulling down on your frame. Which yes are built to take it. but why put more pressure than is needed. I'm just saying the lateral pressure is better than vertical pressure.

SteveH · 06-07-2012, 08:31 AM

Quote:

Originally Posted by purman

I'm just saying the lateral pressure is better than vertical pressure.

The lateral vs vertical pressure is on the "A" frame of the trailer. The forces on the COUPLER are different. With a normal bar type WD hitch the force applied to the coupler at the ball is downward, assuming the hitch is setup correctly.

However with the Andersen, the force applied to the coupler is to the rear, or toward the locking mechanism of the coupler. The locking mechanism may, or maynot be designed to withstand these forces long term.

HowieE · 06-07-2012, 08:39 AM

This is one of the parts that came out of my coupling after 150,000+ miles with Reese. Unfortunately I did not analyzes the insides when I replaced the coupling so I am not sure where it was within the coupling. If you look closely you will see that the failure point on the edge was hammered through not worn.

I would ask those that have commented on the load points of the coupling while using the Andersen rethink things. The static load on the ball/coupling is the weight of the trailer along the vertical . The dynamic loads are the ball/coupling, again vertical or 12 o clock when vied from the side, and the towing force, forward or at 3 o clock. The combination results in a vector probably acting at 2 o clock when viewed from the side. If the coupling were to fail from ware at this point the Atwood couplings used on an Airstream have a pronounced collar that wraps around the base of the coupling and secure the trailer at the shank of the ball. You would see this failure years before the coupling would fail on the road.

If you are looking for a failure point in your hitch assembly I would suggest you keep and eye on the receiver. That is a stock GM receiver with less than 100,000 miles and a Reese. While I don't have a picture the receiver on my Ford is showing a crack in the lower right corner of the receiver.

M2HB · 06-07-2012, 08:40 AM

Quote:

Originally Posted by SteveH

The lateral vs vertical pressure is on the "A" frame of the trailer. The forces on the COUPLER are different. With a normal bar type WD hitch the force applied to the coupler at the ball is downward, assuming the hitch is setup correctly.

However with the Andersen, the force applied to the coupler is to the rear, or toward the locking mechanism of the coupler. The locking mechanism may, or maynot be designed to withstand these forces long term.

That is absolutely correct.
I like the concept of the Anderson WD hitch and if he used vertical chains this issue would be eliminated. I would also use them on gooseneck and 5th wheel assemblies in short bed trucks and mound the hitch just rearward of the axle and tranfer the weight forward.

purman · 06-07-2012, 08:43 AM

I don't believe this is true. The force on the coupler (locking mechanism) is the same no matter what system you use. both systems pull on the bottom of the hitch. it doesn't matter if you pull straight with the chains or pull up on a bar, which then pull straight on the bars at the bottom of the hitch. The result is the same pull on the bottom of the hitch and the same amount of force.

The bottom of the hitch is pulled towards the trailer putting pressure on the pawl/coupler/locking mechanism, with both types of WD hitches. the higher weight bars you use or tighter you tighten the chains, the more forward pressure. thus more pressure on the locking mechanism.

Watch the video, and you will see the pressures put on things is the same just a different way of doing it.

SteveH · 06-07-2012, 08:49 AM

The video, while nice, is a sales product built by Andersen to sell their hitch.

If you understand the Andersen puts force on the "A" frame toward the front, and a bar type WD hitch puts force on the "A" frame downward, there should be no more argument or discussion of the force applied to the coupler.

M2HB · 06-07-2012, 08:50 AM

One reason that Andersen probably didn't use a vertical load is that the chains that he uses keeps the coupler from turning on the ball. Using vertical chains won't accomplish this as well. You could use a vertical chain then cross them diagonally and then it would accomplish the same thing.
There also seems to be a disagreement as the the direction of the forces required to achieve the WD. Think of it as a fulcrum. Then it is easy to see where the forces go. They are different, but they both force the weight forward. It is just different where the "fulcrum" applies the leverage.

SteveH · 06-07-2012, 08:54 AM

Yes, both types of WD hitches put loads on the coupler, just in different directions.

Think of this...The Andersen pulls the "A" frame foward. The bar type WD hitch pulls the "A" frame down.

So then, the Andesen has to put a foward load on the coupler, while the bar type has to put a downward load on the coupler.

HowieE · 06-07-2012, 08:56 AM

There have been several comment that the Andersen put a REARWARD force on the coupling. If that were the case there would be no way the hitch could accomplish WD. The chains exert a rearward force on the bottom of the shaft. In order for that force to result in WD the ball has to be forced forward in the coupling resulting in a contact point within the coupling slightly forward of that from all other WD hitches. WD is the result of forces applied to rotate the receiver clockwise when viewed from the passengers side.

TG Twinkie · 06-07-2012, 09:05 AM

By forcing more weight onto the front axle. Aren't you in effect jacking the back of the TV up and preventing any downward movement with the WD hitch?
The WD prevents any downward movement of either the TV rear end or the trailer front end. Within the limits of the spring bars of course. But what prevents the rear end and trailer tongue from rising? Other than tongue weight.
When the rig goes over a convex bump instead of a concave bump, this puts a force in the upward direction on the ball relieving the tension. In this case the WD is ineffective until the TV and trailer are straddle of the convex bump.
Is this a correct assumption?

purman · 06-07-2012, 09:08 AM

Quote:

Originally Posted by SteveH

The video, while nice, is a sales product built by Andersen to sell their hitch.

If you understand the Andersen puts force on the "A" frame toward the front, and a bar type WD hitch puts force on the "A" frame downward, there should be no more argument or discussion of the force applied to the coupler.

The video shows exactly what happens with a WD hitch. it doesn't matter if it is used for sales or not. The forces are the same.

But the bar type don't put the force downward if it did that it would just put more weight on the top of the ball and thus push the front of the TV up not down.

When you pull up on the bar putting downward pressure on your frame you are pulling laterally on the bar at the bottom of the hitch, the same way as the chains of the Andersen do, but without the downward pressure on the frame. I know it is hard concept to grasp because it would seem it is putting pressure in different spots but it's not. it took my awhile to understand. look up some videos on how WD work. it might become more clear.