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Old 12-11-2013, 09:08 AM   #71
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Originally Posted by dkottum View Post

The distance from tow vehicle receiver to trailer axle is increased with these hitches, compared to "standard" WD hitches, thereby lightening the weight the tow vehicle receiver actually carries. It would not amount to an additional 175 pounds, but something less. For example, Mojo weighed his Hensley equipped Airstream at the tongue jack, and then at the forward side of the Hensley stinger, and reported a 200 pound difference.
I want to be sure I understand what you are saying there. I think you are saying that with the Hensley mounted he measured the "tongue weight" in two places. At the coupler it weighed 25 pounds LESS than at the power jack stem, which is farther astern. Is that right?
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Old 12-11-2013, 09:30 AM   #72
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I agree, the EU car/suv/sav brakes are designed to bring the specific vehicle at maximum load from maximum speed without a trailer to a safe stop. There was NO trailer in the equation or design at all.

The reason non-US trailers, especially EU trailers, are lighter is very simple. When they saw the cheaper, bigger and heavier trailers thinking of coming from the US with electric brakes and weight distribution hitches, the local chaps did not want to loose their gravy train and huge profits. They got legislation passed banning both electric brakes and weight distribution hitches. Simple solution to stifle competition. The EU trailers are much lighter and typically have tongue weights sub 400 pounds and surge brakes. Check out the UK Airstream website:

Overview - Airstream & Company

Thus no EU car makes have had to design their vehicles to support electric brakes and have support for heavier hitch loads and weight distribution hitches. What hitches that exist as an option are not up to the task of over 500 pound loads let alone the stress on the mounting points of a weight distribution hitch. A US person gets to spend a lot of time and money getting the light duty hitch reinforced for heavy duty loads the rest of the car was not designed to handle.

Since the EU cars are designed to their specifications in the EU and are modified with different emissions, brake lights and other small details to come to the US, they have no experience with heavy RV trailers and do not design for that reality.

How to tell if this is true. Was an auxiliary transmission cooler required to tow as the transmission overheated? Were different profile and load rated tires and perhaps wheels have to be installed to tow? The suspension components were not designed to support the higher side and braking loads imposed by the leverage and weight of the trailer.

Did the usual fuel mileage fall off? The drop in fuel milage results from the entire driveline having to work harder to move a car and trailer which exceeds the posted GVW of the car alone plus the additional frontal area wind resistance.

Thus the higher stresses of greater power generation on a continuous basis puts the engine under more stress and wear, the transmission was not rated or designed for this application so it wears out seals and bands, the differential(s), u-joints, suspension components are all under higher stress both accelerating, cruising and decelerating due to the increases in mass and weight.

There are safe design limits for aircraft that include weight, speed, and orientation in flight. These limits are fully detailed in the operations manual and a pilot must know these limits before operation of the aircraft and observe them during flight.

Cars and trucks acre designed with speed ratings, weight ratings and some with tow ratings. Also in the specifications are axle ratings, tire and wheel sizes and the number of legal seats.

Both the aircraft and vehicle will work optimally when within these specifications. Exceeding the numbers in an aircraft (or too slow) can have unfortunate results.

I wonder how folks think they can exceed the design parameters of a surface vehicle safely and attempt to do things with the vehicle for which it was not designed? Perhaps they are engineers and have access to the detailed drawings and component specifications of every part in the vehicle and have calculated which components have a safety margin they can exceed before it breaks.....
If it is all about safety, I think this recent comment by Andy T. is an interesting point to consider. He made this comment in another thread about 10 days ago.

QUOTE
I know of 3 Airsteams that were rolled over this year. A 19' on an F150 and two 31's on 2500 Dodges. Vehicle size is no guaranty of control, how you hitch it up is almost always going to be the most important factor.
END QUOTE

The main point to draw from this is that direct experience matters. And in my world, it matters more than authority. Certainly part of my enthusiasm for my argument is an argument against false authority. When a manufacturer rates his BigDoozy XL 3500 Turbo for 10,000 pounds towing, they are essentially assuming "towing in a straight line with no traffic." What you won't get from this authority is a roadability report with handling characteristics, stopping power with a load, emergency maneuvering videos, or anything else that really matters when towing in the real world. These are fantasized tow vehicles in every way. What you are getting in fact, is simple propaganda that, bigger is better - end of story.

I think the thrust of your post above is all about safety. And my interest is also about safety. Where we differ is how to estimate the safety merits of various TVs. I prefer to get mine by real world trial.
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Old 12-11-2013, 09:41 AM   #73
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Tongue weight

Hi,
I've been reading your threads on towing and tongue weight with great interest. We all stand to learn a lot from each other.
The Sherline Scale website lists recommended tongue/hitch weight to be 11-12% for travel trailers.
Trailer Loading and Towing Guide
I'm not sure how they arrived at this number, but it is more specific than most recommendations you will find. Good luck in your search for the best, safest towing experience.
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Old 12-11-2013, 09:44 AM   #74
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Originally Posted by switz View Post
I agree, the EU car/suv/sav brakes are designed to bring the specific vehicle at maximum load from maximum speed without a trailer to a safe stop. There was NO trailer in the equation or design at all.
What I was trying to say is that brakes that can bring a vehicle travelling at 160mph to a safe stop should have no trouble bringing a vehicle and a trailer travelling at 60mph to a safe stop.

I don't have the mass/velocity/energy equation handy but I am sure the engineers in here can help out.
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Old 12-11-2013, 09:48 AM   #75
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Originally Posted by andreasduess View Post
What I was trying to say is that brakes that can bring a vehicle travelling at 160mph to a safe stop should have no trouble bringing a vehicle and a trailer travelling at 60mph to a safe stop.

I don't have the mass/velocity/energy equation handy but I am sure the engineers in here can help out.
The question IMHO is not if the brakes will bring the tow vehicle and trailer to a safe stop from 60 mph (we all know they will), but in what distance will the tow vehicle come to a stop, and with what stability while being pushed by a 6-10,000 pound trailer?
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Old 12-11-2013, 10:06 AM   #76
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The question IMHO is not if the brakes will bring the tow vehicle and trailer to a safe stop from 60 mph (we all know they will), but in what distance will the tow vehicle come to a stop, and with what stability while being pushed by a 6-10,000 pound trailer?
I realize that any first hand experience is strictly anecdotal, but when I had to bring my un-braked trailer to a stop last summer it turned out not to be a problem.

I was fully expecting to be pushed from the back, in the event the braking took longer than it would have done with a braked trailer, but not dramatically so. Also, I was extra careful not to brake too hard, this was not an emergency situation.

Car and trailer came to a controlled stop within a reasonable distance - I am aware of course that this means nothing, when looking for comparative data but that's the best I have to offer at this time.
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Old 12-11-2013, 10:18 AM   #77
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Originally Posted by SteveH View Post
The question IMHO is not if the brakes will bring the tow vehicle and trailer to a safe stop from 60 mph (we all know they will), but in what distance will the tow vehicle come to a stop, and with what stability while being pushed by a 6-10,000 pound trailer?
I am not sure that the term, "pushed by a trailer" is accurate in all circumstances, or even any circumstances. We have good 4-wheel trailer brakes on our trailers. They engage immediately if your controller is set properly. The trailer can't be said to be pushing the car when it is helping to brake the entire rig, which when hitched right is operating as one unit, I think. At some speeds, and I am sure everyone has tried this, you can pushed the controller lever and use the trailer brakes to stop the whole rig.

I don't think it is as clear as "the trailer pushing the car."
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Old 12-11-2013, 10:22 AM   #78
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Originally Posted by Top View Post
Hi,
I've been reading your threads on towing and tongue weight with great interest. We all stand to learn a lot from each other.
The Sherline Scale website lists recommended tongue/hitch weight to be 11-12% for travel trailers.
Trailer Loading and Towing Guide
I'm not sure how they arrived at this number, but it is more specific than most recommendations you will find. Good luck in your search for the best, safest towing experience.
Thanks Lance. Some interesting information there. I am beginning to think that only direct testing of a specific setup can determine the optimal TW. Such testing at its limits is probably impractical for users.
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Old 12-11-2013, 10:38 AM   #79
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Here's what I said way back in post #5: "My purpose for questioning tongue weight is that I am setting up my new TV, a Chrysler 300 S. I will be towing my 2012 Flying Cloud 25. As this is a sedan, I need to budget my payload carefully. I will only have about 1200 pounds to play with. If I could take 100 pounds off the tongue, FOR EXAMPLE, that would be a significant improvement in my payload budget. "
That is what the spring bars are for. You can use them to redistribute the load from the rear axle of the tow vehicle to the front axle of the tow vehicle and the trailer axle.

Tongue weight has nothing to do with the payload budget. As long as you are within the gross vehicle weight rating of the tow vehicle and trailer you can redistribute the load as you please using the weight distributing hitch.

Another thing. Tongue weight is not graven in stone at the time the trailer is built. It can vary from day to day or hour to hour. Load a sack of groceries into the front of the trailer or the back, changes tongue weight. Filling the water tank changes weight distribution. Using water, thus transferring it from the fresh tank to the gray or black tank, changes weight distribution.

We have already discussed how braking, grade, and winds affect stability.

What I am driving at is this. I understand the question, and it is an interesting one from a theoretical perspective. But in practice, it is meaningless and impossible to answer.
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Old 12-11-2013, 10:46 AM   #80
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Originally Posted by mstephens View Post
I am not sure that the term, "pushed by a trailer" is accurate in all circumstances, or even any circumstances. We have good 4-wheel trailer brakes on our trailers. They engage immediately if your controller is set properly. The trailer can't be said to be pushing the car when it is helping to brake the entire rig, which when hitched right is operating as one unit, I think. At some speeds, and I am sure everyone has tried this, you can pushed the controller lever and use the trailer brakes to stop the whole rig.

I don't think it is as clear as "the trailer pushing the car."
The discussion was about the tow vehicle brakes being adequate the stop the whole rig without trailer brakes.
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Old 12-11-2013, 10:51 AM   #81
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Originally Posted by mstephens View Post
I want to be sure I understand what you are saying there. I think you are saying that with the Hensley mounted he measured the "tongue weight" in two places. At the coupler it weighed 25 pounds LESS than at the power jack stem, which is farther astern. Is that right?
The Hensley/ProPride extends the length of the trailer tongue, which results in less tongue weight carried by the tow vehicle receiver, compared to a "standard" hitch.

Some have posted tongue weights of 1200# or so with a Hensley/ProPride mounted on the tongue, but they have put the scale under the tongue jack. This doesn't accurately indicate what the tow vehicle receiver actually carries.

mojo (I apologize for borrowing your posting mojo) weighed his Hensley-equipped at both the tongue jack, and then farther forward under the stinger where it rests on the tow vehicle receiver. The difference of tongue weight measured at the tongue jack and then at the stinger for his trailer was 200#.

See post number 21 of this thread.
http://www.airforums.com/forums/f464...ml#post1317244

This experiment does not mean you can subtract 200# when using a Hensley, not at all. It indicates the discrepancy of some tongue weight measurements, and the tongue weight carried by the tow vehicle receiver may be much lighter than some are posting.
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Old 12-11-2013, 12:08 PM   #82
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Please note that the scale is graduated in 50# increments, which I submit is about all the accuracy that's needed for T/W.

Above at the 'correct' point under the ball. (no weight bars), after it's settled subsequent to jumping on the haha head.
I do have the referenced 1200# photo available for perusal.

As noted in a previous post there is about a 200lb difference between the two points...I've found the easy solution, remember.

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Old 12-11-2013, 12:18 PM   #83
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Tongue weight has nothing to do with the payload budget.
I disagree. Let me try an example.

Case 1.

Tongue weight of trailer is measured to be 800 pounds. Payload max is 1200 pounds.

Using a WD hitch, we distribute 200 back to the TT axle, which means the remaining 600 pounds is added to the axles of the TV. 1200-600 means I have 600 remaining payload.

Case 2.

Tongue weight of trailer is measured to be 700 pounds. Payload max is again 1200 pounds.

Using a WD hitch, we distribute 200 back to the TT axle, which means the remaining 500 pounds is added to the axles of the TV. 1200-500 means I have 700 remaining payload.

In Case 2 I have 100 pounds more of useable payload after hitching the trailer. No matter how you arrange things, "less TW means more useable payload."
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Old 12-11-2013, 12:19 PM   #84
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The discussion was about the tow vehicle brakes being adequate the stop the whole rig without trailer brakes.
My apology. I mistakenly addressed the wrong case. Sorry!
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