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Old 02-20-2015, 11:30 AM   #21
funpilot
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Quote:
Originally Posted by Padgett View Post
What does that make the effective tongue weight ? I thought most people went the other way, increasing the weight on the trailer axle.

This is getting confusing.
Sorry, I may have been wrong in my observation. My tongue weight is about 620 pounds. I called SwayPro and they told me that I may have the wrong size bars (1000 pounds is what I got) and they are going to send me the 750 bars. They think the 1000 may be too stiff to do what is needed.
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Old 02-20-2015, 02:17 PM   #22
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Originally Posted by funpilot View Post
Sorry, I may have been wrong in my observation. My tongue weight is about 620 pounds. I called SwayPro and they told me that I may have the wrong size bars (1000 pounds is what I got) and they are going to send me the 750 bars. They think the 1000 may be too stiff to do what is needed.
Do you have to cinch them all the way or are they adjustable?
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Old 02-21-2015, 09:49 AM   #23
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Do you have to cinch them all the way or are they adjustable?
This video shows the product. When I use the chains to raise the bar, they do not bend. They are too strong for the tongue weight is what they think.

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Old 02-21-2015, 01:00 PM   #24
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Originally Posted by Padgett View Post
...
Jeep's wheelbase is 115" but it does have a short tail (38" from center of rear wheel to hitch ball) ... My tongue weight was measured at 460 lbs ...
From those numbers, a 460# tongue should put about 612 pounds on the rear axle and take 152# off the front axle, when towing without a WDH. 612# is a lot, but it may come out within the axle ratings if all the other stuff doesn't put it over the top. Whatever fraction 152# is of the unhitched front axle weight is the approximate fraction of tow vehicle steering and braking that is lost while towing. A WDH also reduces the maximum tension loads at the frame mounting points, for those thinking about the hitch receiver.
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Old 02-21-2015, 01:32 PM   #25
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This video shows the product. When I use the chains to raise the bar, they do not bend. They are too strong for the tongue weight is what they think.

That looks like a very nice hitch, particularly for the TM owners who have clearance problems for front slides or swing hitches. "1000# bars" for Sway Pro could be stiffer than those of other companies, but I can't see why you wouldn't be bending bars more as you take in additional links on the chain.

In my case the bars calculate to 645# total on the bar chains, half on each side, for my trailer's 506# tongue weight. And yes, they do visibly bend as they are attached.

The thread with my spreadsheets for weighing on the truck scale and How the Weight Distributing Hitch Works is here:
http://www.trailmanorowners.com/foru...ad.php?t=12552
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Old 02-21-2015, 02:09 PM   #26
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Quote:
Originally Posted by Mr. Adventure View Post
That looks like a very nice hitch, particularly for the TM owners who have clearance problems for front slides or swing hitches. "1000# bars" for Sway Pro could be stiffer than those of other companies, but I can't see why you wouldn't be bending bars more as you take in additional links on the chain.

In my case the bars calculate to 645# total on the bar chains, half on each side, for my trailer's 506# tongue weight. And yes, they do visibly bend as they are attached.

The thread with my spreadsheets for weighing on the truck scale and How the Weight Distributing Hitch Works is here:
http://www.trailmanorowners.com/foru...ad.php?t=12552
Blue Ox is letting me test the new bars and I can return them if they do not change anything. But they are pretty sure that for the WDH to work, the bars need to bend. I cannot get them to bend (not strong enough). I am holding off getting them until the weather is better. They are fine with that.
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Old 02-21-2015, 02:12 PM   #27
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Well sorta. I have a 8.4" rear gear in an axle designed for rock climbing however 460 lbs tongue does not add 612 lbs to the axle. It adds 460lbs to the car. but it adds it in a see-saw effect so has two components: the 460 is added to the car (spread across all four wheels) and then there is a torque monent about the rear axle so the actual change is 230 added to the front and 230 added to the rear then take 152 off the front which results in the net being about 400 added to the rear and 80 to the front. I see very little change in the front (less than a 1/2", this is not exact, takes a good set of scales to know) and the rear drops about an inch.

I need to run some mre calculations but can promise that a 460lb tongue weight does not become a 600 lb load on the rear axle.

Now if you have a lot of distance between the rear axle and the hitch ball that proportion (3:1 for my TV) could change dramatically
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Old 02-21-2015, 02:25 PM   #28
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Gobbly gook

Way too technical, I'd rather camp. I do think we can over think and rethink but should be safe and enjoy our TM's
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Old 02-21-2015, 03:23 PM   #29
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I'm not sure about your math, and I'm not sure where the 152 pounds came from. Let me try it another way.

The attached picture shows the basic operation of a lever. I've shown two pylons bearing some weight, with a beam across them. You can think of the two pylons as being the front and rear axles of the tow vehicle, and the beam as the frame of the vehicle. The distance between the pylons is the wheelbase of the vehicle.

Then I have shown some weight placed on one end of the beam, out beyond the pylons. The added weight causes the beam to act like a teeter-totter - in other words, to pivot. Think of this weight as the hitch weight of the trailer. In this example, the addition of a 500 pound hitch weight causes the pylon on the right to be unweighted by 100 pounds, while the weight on the left pylon increases by 600 pounds.

Makes sense? Hope so. Questions?

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Old 02-21-2015, 04:08 PM   #30
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Well you are half right. The rotational component does add 100lbs to the rear and takes 100 off the front. But if you remove the lever effect (is the above) the purely vertical component (500 lbs) is split between the front and rear axles. What gozinta must match the gozouta.

So if you had a ridgid beam there would be 100+250 added to the rear and 250-100 added to the front.

However a car is not a rigid beam, there is a longitudinal flex compontent (aka structural rigidity and why the roll cage in my Corvette was a suspension component) as well so the weight hung out the back affects the rear axle more than the front. By how much, I do not know, depends on the vehicle, but somewhere in the muddle.
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