Andersen No Sway Weight Distribution

[HowieE]

MIKE

Ask them if the is a dealer closer that you could pick up or could ship on a shorter schedule.

[Airtandem]

Michael; when I bought my Andersen, I ordered through their rep that was located in Mississippi. She covered the center of the US; border to border.
mike

[AWCHIEF]

Originally Posted by Airtandem

Michael; when I bought my Andersen, I ordered through their rep that was located in Mississippi. She covered the center of the US; border to border.
mike

Who was that? I have always been able to deal directly with Dave Andersen. I have a feeling that having it sent overnight would cost as much as the bar itself. If I have too I can make due without it for this trip. If I order on Monday it will be waiting for me when I get back home the following Tuesday. If there is someone local that has one in stock that would be the perfect solution. I do know of one local performance/off-road shop here that sells Andersen fifth wheel systems. I know that they do not stock the WD system. They might have the bar as it is used for Andersens other tow balls also.

[Airtandem]

It was 2 years ago. When I called Andersen, my call was forwarded to that person and I ordered through her. I thought it was interesting that I had to order though Mississippi.

[idroba]

AWChief: Yep, the new Grand Cherokee's have a very high hitch box and you need the drop shank. I was lucky to figure that out prior to ordering the Andersen two years ago. Although you can call Andersen, they work through their dealers and you actually will be paying the dealer but it will be drop shipped from Andersen in Idaho. That way you will get the fastest service. I don't think many dealers actually stock Andersen WD hitches, even if they are actually a dealer. I guess it is simply too costly for them to stock the various sizes and parts, considering the volume sold.

[AWCHIEF]

Ok, problem taken care of. I gave the Andersen office a call on the off chance that someone was in this morning. Dave answered the phone. Told him what I needed and he said "No problem". He is sending out a new drop bar tomorrow morning, it will be here by the time I get back from Canopener. $90 w/free shipping via ground UPS. Overnight would have been another $90 (ouch).

[TWerner]

Hi idroba and AWCHIEF,

Full disclosure on my first post. I don't own an Airstream. My sister does. I trailer a compact tractor, and I learned about weight distributing hitches after towing a 6800lb load though the mountains in the snow without one. It was supposed to be 5900, which is less than what my owners manual said I could tow, but it turned out the tractor had loaded tires. The info on the back of my truck says 4400lbs wt bearing, 7900 weight distributing. So I was way over my limit. I also now know that the trailer I borrowed doesn't have brakes when hooked up just to the 7 pin plug. It has a different system to connect to a dump truck. Never again, so I'm buying a WD hitch for my own trailer.

That said, my reason for joining here is because this site has far and away the most feedback on the Andersen WD hitch, which prior to reading that thread, was my first choice. Now I don't know, but I think it may work if the trailer tongue and my hitch are at the same height.

You see, I read a lot of the now closed huge thread that turned into an argument between Howie and Doug. There is a lot of variation in opinion on how much weight it can distribute. I have a simple theory on that phenomenon, that I didn't see anybody else postulate, and since you both have Jeeps, you may be the perfect two to help prove or disprove my hypothesis.

A WD hitch works by applying torque on the tow vehicle through the hitch. On the standard type, you are pulling up on a long bar which acts like a lever to apply torque to a shorter bar. The shorter bar being the vertical drop bar. Since the drop bar is short compared to the horizontal levers, small changes in its length won't affect the torque significantly.

The Andersen system is different. It is applying torque by pushing on the ball and pulling on the chains below the coupling. So there are two short levers, each being half the distance between the chain attachment point and the receiver ball. Those levers are very short compared to a standard system, just a few inches long.

Think of the Andersen as similar to a cross shaped lug wrench made from two 8" long bars. If you attached it to a bolt head on the side of your vehicle's receiver, you would push forward on the top grip and pull back on the bottom grip to press down on the front wheels. Each of your levers is 4" long, so you don't have much leverage. That's how Andersen's weight distribution works, and is why there is a lot of back pressure on the couplers.

A standard weight distributing hitch would be analogous to placing a 3' socket wrench on that bolt with a small downward angle. You would pull up on the wrench end to apply torque to the receiver. If you now add a drop bar to your receiver, and place that imaginary bolt head 6" below the receiver, that 6" bar is acting like a lever against you. Now both your handles are under your pivot point. . With the bar system, your wrench handle is 3' long, so your leverage went down very very little. With the lug wrench style of the Andersen, you've lost almost all your leverage.

So after all that, I wanted to know if you had measured the weight redistribution of you Andersen systems at a scale, to see if it is less effective when the ball is lower than the tow vehicles receiver hitch? HowieE, the most vocal proponent of this hitch said his rear axle load dropped from 5120 to 5000lbs using the Andersen. 4400 unloaded. That's 920# down to 800# or a 15% decrease in rear axle load. I don't know if 15% is good, but it seems like you'd want more than that.

Thanks,
Todd

[idroba]

I think you are saying that because of the higher hitch box on the 2011 and up Jeep Grand Cherokee we get more leverage and thus higher weight distribution. Is that right?

I have thought long and hard about that very same idea, but have never voiced it here on the forum, because there have been so many other thoughts, comments and ideas I felt it would confuse the issue of the Andersen more and get lost in the noise.

Cut to the chase: Yes, I believe that with a higher hitch box such as we have on the GC vs. the standard hitch height on the Airstream allows more forward weight distribution with the Andersen hitch. That is once the shank is moved up vs. the standard Andersen ball/chain difference, there is a multiplying effect on how much weight can be transferred.

[slowmover]

Owners of said hitch have, for the most part, failed to give before/after weight scale readings.

There is a lot of variation in opinion on how much weight it can distribute.

No, it has a maximum of 200-lbs. Suitable for the very smallest TT itself requiring WD, but not for the vast majority of articulated vehcles. Numbers aren't opinions . . the opinions of those who advocate this hitch put a substantial burden on their own credibility with others.

.

[Road Ruler]

TW and Idroba....

I think this is a ground breaking revelation and you are on to something with the idea of the hitch box height being a factor in the Andersen's ability/inability, to transfer weight.

A good point and thinking there is more to it. It has to do with tire size diameter (axle height), hitch box height, rear overhang length, wheel base, weight of vehicle.

Note.. in an extreme example if the vehicle sat very high, and the axles were high (large tires) and the hitch box was very low to the ground I would suggest the Andersen would actually provide no WD at all.

Or, for the Andersen to work, distribute weight, the hitch box must sit high on the rear of the vehicle relative to the axle height.

This explains why, and I can see now why this hitch is so lame (small amounts of weight distribution) in certain applications.

Some real world testing really needs to be done to prove the theory.

[TWerner]

Originally Posted by idroba

I think you are saying that because of the higher hitch box on the 2011 and up Jeep Grand Cherokee we get more leverage and thus higher weight distribution. Is that right?

I think that if the ball is above the shank and the triangular plate is below the shank, then you should have maximum torque and the most weight redistribution the hitch is capable of. Once the ball drops below the shank, I believe you are losing torque. However, having drawn it out, I think it is more that the closer the ball housing is to the height of the rear axle, the more torque you will have as you are closer to the rear axle.

[TWerner]

edit:
Road Ruler, that made me reconsider, and I think I am wrong, actually. I think what we are looking at is a tall skinny T that Andersen lay on it's side.

The top part of the T, or the cross part, is the distance between the ball and chain plate. The long part of the T is the distance from the hitch to the front axle. The longer the distance to the front axle, the less pressure you can apply to it. Probably true for any WD hitch, but the Andersen is more limited in how much torque it can generate due to the short levers. I guess it's the wheel base and not the hitch height that matters on all of these WD hitches. The Andersen may work fine on my shortish wheel base Trailblazer.

[Ron Gratz]

Originally Posted by TWerner

The top part of the T, or the cross part, is the distance between the ball and chain plate. The long part of the T is the distance from the hitch to the front axle. The longer the distance to the front axle, the less pressure you can apply to it. Probably true for any WD hitch, but the Andersen is more limited in how much torque it can generate due to the short levers. I guess it's the wheel base and not the hitch height that matters on all of these WD hitches. The Andersen may work fine on my shortish wheel base Trailblazer.

Generation of torque requires two equal forces acting in opposite directions and separated by some distance.
The torque is equal to the product of force magnitude times distance between the forces.

The chain of the Andersen WDH produces a rearward-acting force on the triangular plate. That force is opposed by an equal forward-acting force exerted by the coupler against the ball.
If you move the vertical location of the forces up or down by changing the hitch height, you do not change the magnitude of torque applied to the TV as long as the vertical distance between ball and plate does not change.

The restoration of load on the TV's front axle depends, in part, on the magnitude of WDH-generated torque divided by wheelbase. The rear axle acts as the pivot point.

A secondary contribution to load restoration arises from the fact that the WDH produces a net upward force on the hitch head via the front ends of the WD bars.
This net upward force multiplied by the distance from hitch head to TV's rear axle generates additional pitch-axis torque.
This additional torque, divided by wheelbase, results in additional front-axle load restoration.

The TV's wheelbase does not affect how much WD bar torque is required.
A shorter wheelbase, with a given ball overhang distance, will result in more load being removed from the front axle.
A shorter wheelbase, with a given amount of WDH torque, will result in more load being restored to the front axle.
The wheelbase effects cancel each other out. The amount of WDH torque required depends only on tongue weight and ball overhang distance.

The WD shortcoming of the Andersen WDH is its approximately 6" moment arm compared to an approximately 28" moment arm for a "conventional" hitch.
Neither the TV's hitch height nor its wheelbase can compensate for that shortcoming.

Ron

[TWerner]

What is the tension on the chains of the andersen hitch versus the lift on the conventional arms? The lever difference is about 4.67. If you crank the chains to 2000 lbs of tension, it would generate about 1000 ft lbs of torque. To do the same, it would take about 430 lbs on the ends of the conventional arms, or 215 each. Correct?

[Ron Gratz]

Originally Posted by TWerner

What is the tension on the chains of the andersen hitch versus the lift on the conventional arms? The lever difference is about 4.67. If you crank the chains to 2000 lbs of tension, it would generate about 1000 ft lbs of torque. To do the same, it would take about 430 lbs on the ends of the conventional arms, or 215 each. Correct?

Correct.

The upward force on the end of each conventional WD bar is roughly equal to the trailer's tongue weight.

If an upward force of 1000# were applied to each 28" bar, the resulting torque would be 4667 lb-ft.

Ron

[TG Twinkie]

I have towed our 26' Argosy over 9,000 miles this year using the Andersen hitch. Along with the original Marvel coupler.
My TV is an '08 Tundra 5.7 Ltr V8.
The Andersen has worked well for me. No sway, no porpoising, no handling problems. And no coupler problems.
Just my $.02 worth.

[dmand001]

Suppose the technicalities stated are meaningful though I'm just simple-minded. I just go by the Andersen instructional manual and go by fender height measurements.

TG Twinkie, I'm considering to trade in my SUV for a new tundra 5.7 w/ tow package, 4x4 off-road one but debating the change from SUV/Truck? The Tundra though seems wonderful, think, I'm going for it.

[Ganaraska]

T Werner you are onto something. This is one of the advantages of the Anderson hitch, it does not redistribute weight like other hitches. A big advantage when you have a big heavy duty tow vehicle and don't need much weight distribution. It keeps you from beating your Airstream to death with thousand pound bars. It puts more weight on the rear of the tow vehicle which in the case of a big truck, can use more weight on the back for proper weight distribution.

I'm surprised this even needs to be explained. I thought it was obvious at a glance that this is how the Anderson works.

But maybe it is not obvious. When Can Am Andy tried to point out this feature, which limits the hitch's effectiveness on passenger cars, he got a lot of flak for it. I thought this was pure prejudice but maybe his critics don't understand how the hitch works.

[TG Twinkie]

dmand001;
You won't be disappointed with a Tundra.

[dkottum]

Ganaraska, I think you're missing something comparing the flexibility of weight distribution bars to Andersen's urethane bushing.

The weight distribution bars do flex when going over uneven roadways or into steep driveways. The Andersen depends on the remaining flexibility in the urethane bushings after it's (weak) attempt at weight distribution to take this vertical movement. Take a look at a squished Andersen urethane bushing and decide for yourself how much flexibility is remaining.

The notion that heavy duty trucks don't need weight distribution is another story. If true then don't use thousand pound w.d. bars, use 400# bars. You will have poor weight distribution like the Andersen, but a nice flexible weight distribution hitch.