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SLNugget · 09-05-2012, 05:36 PM

Not to be arguementative, but, it is not possible for there to be no movement between the ball and coupler IMHO. There may be no rotational movement, but, I think there will be movement when the tv and trailer go over different levels. An extreme example would be a speed bump. Am I incorrect in this assumption? My concern are the forces acting on the coupler. Most were not designed to have force applied to the rear of the "pocket" and locking mechanism, rather to withstand a pulling force against the front of the "pocket". I am trying to like the Andersen but these are some of the reservations I am having.

dznf0g · 09-05-2012, 05:57 PM

Quote:

Originally Posted by SLNugget

Not to be arguementative, but, it is not possible for there to be no movement between the ball and coupler IMHO. There may be no rotational movement, but, I think there will be movement when the tv and trailer go over different levels. An extreme example would be a speed bump. Am I incorrect in this assumption? My concern are the forces acting on the coupler. Most were not designed to have force applied to the rear of the "pocket" and locking mechanism, rather to withstand a pulling force against the front of the "pocket". I am trying to like the Andersen but these are some of the reservations I am having.

You're correct, just like a PP or HAHA, there is no rotational movement, but there is vertical movement.

AWCHIEF · 09-05-2012, 06:52 PM

Quote:

Originally Posted by SLNugget

Not to be arguementative, but, it is not possible for there to be no movement between the ball and coupler IMHO. There may be no rotational movement, but, I think there will be movement when the tv and trailer go over different levels. An extreme example would be a speed bump. Am I incorrect in this assumption? My concern are the forces acting on the coupler. Most were not designed to have force applied to the rear of the "pocket" and locking mechanism, rather to withstand a pulling force against the front of the "pocket". I am trying to like the Andersen but these are some of the reservations I am having.

If you read the post from actual owners you will see that this is truly not an issue. Yes, there is some movement, but it is very little and no damage of any kind has been contributed to the Andersen. Also I would suggest that if you have not already done so check out the videos on the Andersen site.

idroba · 09-05-2012, 07:22 PM

Quote:

Originally Posted by SLNugget

My concern are the forces acting on the coupler. Most were not designed to have force applied to the rear of the "pocket" and locking mechanism, rather to withstand a pulling force against the front of the "pocket". I am trying to like the Andersen but these are some of the reservations I am having.

This has been covered numerous times in this rather lengthy thread. Couplers are not designed stronger in one direction vs another. If you think of it, as a TV and trailer are going downhill, with no brakes applied, the trailer is pushing the TV from the rear of the ball. If the TV is braking the and there are no brakes on the trailer (very common in the real world, especially with horse trailers and their couplers) the trailer is pushing even harder on the rear of the ball. We back up trailers also, that puts forces on the rear of the coupler. Couplers can take forces on their rear components.

And yes, couplers do wear out like everything else. However, as was pointed out a few posts ago, the movement in the coupler is very minimal, to the point that Andersen does not even recommend grease on the ball (I put a little on anyway because of the small pitch and yaw movements on the ball).

I am personally content that the coupler will take any load that the Andersen imposes on it and will not suffer, nor fail prematurely or in any catastrophic way.

In addition, in the exceptionally unlikely event of failure of the rear locking mechanism of a coupler, the only thing that would be lost is the weight distributing characteristic of the hitch. The tongue weight would still hold the trailer on the ball. The WD chains would still be there to do the pulling, as well as the ball itself.

The rear coupler forces are a non issue in my mind.

Wazbro · 09-05-2012, 07:26 PM

SLNugget it is important to check the condition of your coupler occasionally no matter what hitch you are using.

purman · 09-05-2012, 08:03 PM

Check post #318 for pictures of wear on the ball. Yes there is a little movement but not much..

Kosm1o · 09-05-2012, 08:04 PM

I agree about the inspection but also agre with idroba. Problem with coupler is over-blown.

SLNugget · 09-05-2012, 11:47 PM

I am talking about couplers that may be 40+ years old. Surely these older generation couplers have worn (and yes I do inspect mine) and become weaker with time and use.

Also, think about what actually happens to transfer weight to the front axle of the TV. The trailer tongue and rear of the TV are being raised to effect the transfer. So now the coupler locking mechanism is actually exerting a lifting effort on the ball. How much is that force? I don't know but I am sure someone will offer an opinion or know how to figure it out. It may be minimal and amount to nothing. I just don't know. I do know the coupler locking device was not designed 40+ years ago to be used in this manner. Will it work, it obviously does. How long will it continue to work before there is possibly a material failure? Is the lifting force enough to uncouple the trailer from the ball if the locking mechanism fails? I think these are valid concerns

purman · 09-06-2012, 06:59 AM

Quote:

Originally Posted by SLNugget

I am talking about couplers that may be 40+ years old. Surely these older generation couplers have worn (and yes I do inspect mine) and become weaker with time and use.

Also, think about what actually happens to transfer weight to the front axle of the TV. The trailer tongue and rear of the TV are being raised to effect the transfer. So now the coupler locking mechanism is actually exerting a lifting effort on the ball. How much is that force? I don't know but I am sure someone will offer an opinion or know how to figure it out. It may be minimal and amount to nothing. I just don't know. I do know the coupler locking device was not designed 40+ years ago to be used in this manner. Will it work, it obviously does. How long will it continue to work before there is possibly a material failure? Is the lifting force enough to uncouple the trailer from the ball if the locking mechanism fails? I think these are valid concerns

Go and look at post #318. You can see by the wear points on the ball the locking mechanism is not taking the brunt of the forces being applied to the ball during weight transfer.

SLNugget · 09-06-2012, 12:57 PM

Thank you Jason. I did look at that post and the photos.

I am still concerned about the forces being applied/transferred through the ball/coupler interface.

I apologize for hijacking this Andersen user thread with my technical questions.

Stan

Wazbro · 09-06-2012, 01:47 PM

It doesn't lift the coupler at all, the chains pull back on the plate on the bottom of the ball shaft and coupler pushes forward on the ball this twists the hitch head lifting the ball (not coupler) and adding "weight" to the front of the vehicle.

purman · 09-06-2012, 02:15 PM

Quote:

Originally Posted by SLNugget

Thank you Jason. I did look at that post and the photos.

I am still concerned about the forces being applied/transferred through the ball/coupler interface.

I apologize for hijacking this Andersen user thread with my technical questions.

Stan

The weight doesn't go straight back. so the weight isn't all on the lock. I talked to Andersen about this and it was not a concern of theirs. Plenty of us are using it here, and if you check other rv forums they are too. You will only find concerns about the coupler issue with people who are not using the hitch.

HowieE · 09-06-2012, 02:51 PM

Well I decided the TV would not drop again whether or not the jack is extended.

I have a piece of wooden dowel in where the 5/16 roll pin will go once I put the ball shaft back in the hitch.

For those that think they will move the ball to align with the hitch you had better have a very long lever. You will note the tool marks on the tapered shaft. They produce a complimentary set of grooves in the brake material and after a few miles that has the similar effect a bolt treads in a nut. Those with very light trailers may be able to adjust the shaft but I doubt it.

HowieE · 09-06-2012, 05:32 PM

I don't know if mine has enough room at the bottom to put a pin in. It hasn't pushed down as far as yours has..

I got notice via e mail that the above was posted to the tread but it doesn't appear on the tread. Not sure what may have happened.

Here is another picture to illustrate what I did.

I assume all of the hitches will have enough room below the hitch body to accept a roll pin. This took about an hour to complete with a grinder and hand drill.

Note on the picture in the above post, I wanted the pin as close to the body as possible to limit any movement should the shaft slip out. Since the triangular plate fits close to the body I had to grind clearance into the triangular plate for the roll pin.

AWCHIEF · 09-07-2012, 06:28 AM

Howie, I beg to differ, but I use a screwdriver that is 14 inches long to move the ball. No problem as there is no weight on the ball shaft when I turn it. If it does hang up a tap on the bottom of the shaft frees it up. With the full weight of the trailer on the ball I don’t think that I could turn it using only human power or would have a reason to even try. I don't think the size of the trailer would make any difference. I have done this several times as it is actually normal for me to unhook and hook up at different angles.
About your modification, it should take care of any concerns of the shaft inadvertently coming out. Just curious about one aspect, have you checked with Andersen on how or if it will it will affect your warranty/liability with them.

mstephens · 09-07-2012, 07:35 AM

Quote:

Originally Posted by Andrew T

First of all I have not interest in any hitch company I just know what we have used over the last 43 years on thousands of combinations. I am pretty aware of the strengths and Sometimes the devil you know.... I am pretty leary about recomending something I have not tried myself rather extensively. For example we put 15000 miles on two Hensley's before we ever installed one for a customer.

I should likely buy an Anderson to try out. It is just over the years I have bought a lot of hitches that I wound up sitting in the corner after some testing. With the Anderson I just can't seem to make sence of it when I do the math, maybe I am missing something.

Take the 34' & Excursion example. To push the front axle of an Excursion down 1/4" requires about 200 pounds of weight. The front axle is just over 16' from the ball that means the hitch needs to exert 3200 pounds of torque on the reciever to transfer that weight. Likely 400 pounds is being transfered to the excursion's rear axle 5' away so that will take another 2000 pounds of torque for a total of 5200 ft pounds of torque on the receiver.

To leverage that torque we have the distance between the ball and the chain attachment on the bottom of the ball mount Likely about 9". So the chains have to pull back with a force of just under 7000 pounds to create the necessary leverage. with that force the bolt through the clevis pin is going to bend and I think the links would also stretch.

We occasionally break a larger link on a conventional torsion bar chain which has 28" of leverage to work with. I don't think the puck that slides up and down in the rear of the coupler was designed to operate with 7000 pounds of force against it. take a good look under your coupler this is not a particularly robust area. Again it might be fine but what happens after 50,000 miles? Underbraking your trailer should still be pulling on the tow vehicle and even without it is a short duration force not a constant.

One other element is that this hitch will always transfer weight in the direction the trailer is pointing. A conventional weight distribution hitch set up properly will always transfer weight to the front wheels of the tow vehicle instead of the outside rear wheel in a turn.

On the other hand I like the placement of the friction pad and the light weight for hooking up and disconnecting.

Just to clarify my concern.

Andrew T

This was an interesting thread to read, and this is an interesting hitch design. The post by Andrew T here, seems to correctly analyze the WD operation of the hitch, and that makes me scratch my head and wonder if those chains can really pull back with that much force? It seems the most awkward and difficult way of achieving WD.

The reports by users seem to validate the operation, making it all the more mysterious to me.

WD bars use the simplest torque principle. The distance from the TV front axle to the point of lift on the far end of the bar provides enormous leverage on the order of 12:1. Direction of force is vertical, which makes it convenient to use gravity to supply the force.

The hitch here also uses torque, but the leverage is wickedly reduced compared to the WD bar. The distance from the midline of the receiver to the plate where that chains attached looks like less than a foot. The force needed to rotate the TV frame about the front axle is here a horizontal strain force on the chains. As T. Andrew calculated, it would look like several thousand pounds of force needed to affect a few hundred pounds of WD.

Obviously it works because people have them and are using them. But it sure is a brain twister to see how it works.

Andrew T -- did you try one?

AWCHIEF · 09-07-2012, 07:55 AM

I wish the folks that continue to find fault with the system without even taking the time to try one out would put out a few bucks and try it for themselves. The Andersen comes with a 90 day full money back guarantee. If you are not happy with the system for any reason it can be returned. According to Dave Anderson not one unit has been returned to them. I have not read one report (on several different forums) from an actual user that was negative in any way if the recommendations put out by Andersen are followed.

purman · 09-07-2012, 08:17 AM

I have to agree with AWCHIEF here.

Andrew T has many years of experience and I respect his opinion on WD hitches. BUT HE IS WRONG ON THIS ONE. He admits he has never seen one in person or touched one. How on earth can you make a judgment on WD you have never seen or used?

So to say it doesn't work is a very ignorant statement when you haven't even seen it or used it.

There are 1,000's of people using this WD, and it does distribute weight, and it does it very well...

Mstephens: if you read the whole thread then I don't see why you would have any questions as to it working? IT DOES.

I haven't put mine on the scales (but plenty have and the numbers are out there) but when my tire to wheel well measurements are within a 1/4 or original, I know it is distribution weight.. END OF DISCUSSION.

The coupler issue should also be put to rest. As the pictures show the locking mechanism is NOT I repeat, is NOTtaking the brunt of the weight when hooked up.

It becomes frustrating when issues have been addressed and people still continue to bring them up without touching or using the Andersen hitch.

IT DOES WORK AND IT DOESN'T DESTROY YOU COUPLER..

SteveH · 09-07-2012, 08:33 AM

Well I have "bit the bullet" and ordered an Andersen, but not for the Airstream, for a smaller trailer that I also have, a 17' Casita.

I've been using one of the light duty, single bar WD hitches on it, and it too has it's issues, so I will try the Andersen and see for myself how good it is.

It will probably take a while, but a report will follow.

mstephens · 09-07-2012, 08:40 AM

For the fellows making the defense remarks let me say this. If a person showed me a radio with a 5 watt transistor on the output and claimed it put out 50 watts, I would not need to "buy one and try it" to know that a 5 watt radio can't put out 50 watts. Likewise, I don't need to eat 10 apples to know that 3 apples plus 7 apples is equal to 10 apples.

The laws of physics apply at the Anderson works the same as they apply at the engineering tables of any hitch manufacturer. There is no magic in the world of any kind. Hitches work on principles that are as old as the universe. They can be understood with nothing more than a pencil, paper and calculator.

Can you imagine the absurdity of buying everything based on manufacturer's advertising just to see how it works? Suppose you want a new stereo? What would you do -- buy 20 of them to "try them out?" Well, you might, but I don't. I generally make some analysis first on paper.

I was mostly inquiring of T. Andrew to see if he had taken his inquiry any farther because it appeared to me that he described the physical action of the hitch correctly.

I am curious how it works. I didn't criticize anyone's decision to buy one, nor did I challenge anyone's claims about their experience. If you thought I did, I apologize profusely for ruffling up your feathers. I thought it was a public thread for public comment. If it was intended as just a "fan club thread" for owners I apologize for intruding.