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Author Topic: hitch weights for dummies  (Read 3186 times)

deber

  • Guest
hitch weights for dummies
« on: June 05, 2005, 09:15:59 AM »
Hi folks,
We've been trying to understand the significance of the hitch weight number provided by the manufacturer....and we failed. 
Here's what we know:
1) Hitch weight is important
2) We don't know enough to know what to ask.

We found this, and decided we must understand hitch weights thoroughly:
Quote
About hitch weights: One thing that is absolutely clear about highway control when towing a fifth wheel or trailer coach is that proper hitch weight is critical to the prevention of an accident. RVCG looks at the optimum hitch weights that have been established by the RV industry for over 30 years and uses that data to determine extremes. It has been proven beyond a shadow of a doubt that too light of a hitch weight has caused more accidents than all other deficiencies combined and that too heavy of a hitch weight is the second most common cause of trailer-related accidents. RVCG uses the manufacturer's own numbers backed up by consumer input to arrive at this part of the Highway Control Rating.

Primarily, right now we are trying to figure out how manufacturers arrive at their hitch weight number.  I'm not detecting a formula based on GVWR or otherwise.  We are still planning on purchasing a 5th wheel.

Carl L

  • Forum Staff
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  • Posts: 7303
Re: hitch weights for dummies
« Reply #1 on: June 05, 2005, 01:33:35 PM »
Hi folks,
We've been trying to understand the significance of the hitch weight number provided by the manufacturer....and we failed. 
Here's what we know:
1) Hitch weight is important
2) We don't know enough to know what to ask.

We found this, and decided we must understand hitch weights thoroughly:
Primarily, right now we are trying to figure out how manufacturers arrive at their hitch weight number.  I'm not detecting a formula based on GVWR or otherwise.  We are still planning on purchasing a 5th wheel.

Hitch weight is merely the measure of the trailer's weight that bears on the hitch coupler.   It is measured directly by scales or a hydraulic "pot" scale.    Trailer stability depends upon it being in a weight forward condition to couple it mechanically to the tow vehicle.  In other words the trailer's center of gravity should be forward of its axles.  If it moved aft of the axles, the trailer would be in a wild oversteer condition -- ie. unstable.    Experience indicates that that weight should range between 11% and 15 to 20% or so of the trailer's weight, as loaded.   

As loaded since the load in the trailer can vary that.   The biggest single variable load in a trailer is fresh water -- a forty gallon tank weighs 320 lbs.   If you look at well-designed trailers you will find that the tank is located ahead of the axles so that a full tank can tend to stabilize the trailer.
Carl L/LA   [Forum Staff]  KI6SEZ

Prowler 23LV TT pulled by a '95 Ford Bronco

N Smock

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  • Posts: 246
Re: hitch weights for dummies
« Reply #2 on: June 06, 2005, 06:38:12 AM »
Deb & Jere

Attached is a spread sheet that you might find usefull. Just change the numbers in blue to customize the result.


Nelson

deber

  • Guest
Re: hitch weights for dummies
« Reply #3 on: June 06, 2005, 10:04:42 PM »
Thank you.  I had never heard that about the water tank.  Makes sense.

Spreadsheet is great and will definitely be used.  Thanks again!

Deb & Jere

 

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