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Old 12-17-2006, 06:26 PM   #15
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1975 29' Ambassador
Reno , Nevada
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The further forward of the axles the trailer's center of mass lies, the less influence it will have to sway the trailer and the less lateral force it can put on the ball.
I am not too sure about the latter one. If the mass moves forward towards the ball it will provide a greater moment about the center of rotation of the trailer and that means more lateral force on the ball? - it should have greater damping or opposition to trailer rotations, though.

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Old 12-17-2006, 06:32 PM   #16
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1977 31' Sovereign
Riverhead , New York
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Originally Posted by JimGolden
It was on new ST tires. Yes, I know now (I didn't at the time) they're rated for only 65mph,
Jim just one point, that's not correct, the MPH is based on load and tire pressure, they can exceed 65 safely.

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Old 12-17-2006, 06:33 PM   #17
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hi jim

you may already know these things....

-there is a hensley yahoo group with 'for sale' hitches occasionally.

hensleyarrowrvhitchclub : Hensley Arrow RV Trailer Hitch Club

i think hunter who does the yahoo a/s group started it...

they recently had one listed for 2k and i've seen them for 1500$...

but they go fast.

-the virtual pivot point (vpp) is calculated at 47inches? approx...

-but when turning this gets much much shorter...

-we've got a thread going for haha users...

and early in that thread are links to the patent and a thread on another forum...

with math and diagrams of haha's long but some posts in it are useful...

-the haha can be used sans w/d bars and the antisway features remain.

-a good thing about buying one vs building one can b moved to another trailer....

should you ever out grow 'mon-stream'...

all of the true things that i am about to tell you are shameless lies. l.b.j.

we are here on earth to fart around. don't let anybody tell you any different. k.v.
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Old 12-17-2006, 06:44 PM   #18
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2005 28' Safari
Port Orchard , Washington
Join Date: Mar 2006
Posts: 95
"Weight distribution" was popularized 20 or more years ago.
That was when pickups were 2WD and big block gas powered.
The front axle was maybe 500# heavier than the rear. You needed weight distribution to keep the front wheels on the ground and streeing the truck.

New world. Your diesel pickup, just like mine, has more than 1,200# excess front axle weight, due to the motor.

Your trailer has a hitch weight of 700-900#.
Put that on a 4' lever, fulcrum at the rear axle, and other lever is 14' to the front axle.
So you get 3 to one aprox. advantage. I will use 750# so it is easy to figure.

Add 750# to hitch, it puts 750# to the rear axle,
transfers 250# from the front axle to the rear axle.
Giving 1000# more load on the rear and 250# less on the front axle.

The desired effect of weight distribution is to BALENCE the tow vehicle.

With your truck, and any tounge weight less than 700#, no weight distribution is needed.
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Old 12-17-2006, 08:21 PM   #19
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1975 27' Overlander
High River , Alberta
Join Date: Aug 2006
Posts: 385
I just wanted to add a few comments based on what I've observed and learned.

It's worth noting that plenty of boats tow just fine with about 7 to 9% tongue weight. Also, European "caravans" are typically designed with 7% tongue weight (weight distributing is virtually unknown there, it seems).

I'd guess that a utility trailer with a balanced, low profile load will perform just fine with 10% tongue weight. It's just a good rule of thumb in those cases; it might do fine with less than 10%. Boats, of course, are relatively low profile, especially I/O's. European caravans are designed with a low centre of gravity and kitchens and baths are often oriented to the middle of the trailer. And slides are nowhere to be seen.

Polar inertia (movement of mass around a centre point, as I understand it, or "moment about the center of rotation" as Leipper described it) seems to be the factor that determines how much tongue weight is needed for stable towing. A trailer that's light in the middle, but heavy at either end (or both ends) needs more tongue weight. A trailer that's top heavy (like one with a slide out) also needs more tongue weight. Keep the mass very compact and close to the axle, and relatively little tongue weight would be needed. However, loading ahead of the axle is going to be safer than loading behind.

I once read a helpful illustration of polar inertia in an article about the advantages of mid-engine sports cars. As I recall, it suggested taking an egg carton with four eggs (or just thinking about it). Put all the eggs in the middle of the carton, and hold it in your hand. Gauge the resistance to twisting/turning. Then put the eggs at one end, or two eggs at each end. Note how more effort is need to start the turn, but how inertia makes it harder to stop the turn. The point was to illustrate the superior maneuverablity and handling of mid-engine cars. You can imagine how a tail heavy trailer would be rather miserable to tow - a pendulum swinging out behind.
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Old 01-05-2007, 12:54 PM   #20
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St. Catharines , South Western Ontario
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Good info Albert. When my dad was selling TT's back in the 60's I recall him preferring the TT's that were designed with most of the weight in the centre, on the axles. His comment was that they towed better. I don't know if he actually new why or if it was from his vast towing experience.

Back then he used an Equalizer Brand WDH and a Kelsey Hayes brake controller. Receiver was a custom made, that was supported in the centre. I continue to use that superior formula even today. To effectively transfer weight the receiver needs to be flex free and unfortunately most receivers are not.


Airstreams..... The best towing trailers on the planet!
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