Another Weight Distribution Question

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ADubois

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I've been reading some of the post about weight distribution hitches. In one thread it was mentioned that the rating for the WDH springs should be at least equal to the tongue weight plus 200 lbs if it's a lightly sprung TV.

My question is would the weight in the back of the truck say, wood, bikes, etc. etc. matter for the rating of the WDH springs? I was thinking it might if the purpose is to distribute the load of the truck and trailer both. I'm going to need to purchase a WDH set up. I quite normally have weight in the back of the truck.

Thank you
Alan
 

Carl L

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ADubois said:
I've been reading some of the post about weight distribution hitches. In one thread it was mentioned that the rating for the WDH springs should be at least equal to the tongue weight plus 200 lbs if it's a lightly sprung TV.

My question is would the weight in the back of the truck say, wood, bikes, etc. etc. matter for the rating of the WDH springs? I was thinking it might if the purpose is to distribute the load of the truck and trailer both. I'm going to need to purchase a WDH set up. I quite normally have weight in the back of the truck.

Not as far as rating your spring bars.? ?Truck payload is irrelevant for them.? HOWEVER, the load in your bed is going to effect the rating of your rear truck axle.? ?The hitch system, if working right will add roughly half the tongue weight of the trailer to that axle.? Now you pile in a payload on top of that.? So check out your headroom on that rear axle rating.? ?The trailer and payload + the tare weight of your truck are going to contribute to your gross combined vehicle weight (GCVW).? Be sure you are not pushing the GCVW rating of your truck? -- figured with some headroom allowed.
 

Jim Dick

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Hi Alan,

What Carl said. :)

I work part time at a dealership. When we need to install weight distribution systems we take 10% of the GVWR of the trailer. If it's a 7800#  trailer we install 800# bars. Some people will ask for larger bars in anticipation of upgrading the trailer in the future. Doesn't help with the current trailer but saves money later on if one should get a larger trailer.

 

Gary RV_Wizard

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Carl,
Is it not true that oversize spring bars would allow a greater percentage of the tongue weight to be transferred to the front axle?  I.e.., more than the 50% that we usually recommend?  If that is so, then you could compensate for other loads (payload in the bed) by tightening up the bars and transferring more of the tongue weight forward, thus reducing the overall load on the rear axle.

Example:
1000# of gear in the truck bed of a pick-up
800# trailer tongue weight
Rear axle load = 1000 + 800 = 1800# (without WD)

Now add a WD hitch with 1000# spring bars.  Tighten them up a bit and they should transfer 50% of the tongue weight (400#) forward to the front axle, so now the rear axle load looks like this:    1000 + 800/2 = 1400#

Tighten up the bars a couple more notches and transfer 75% of the tongue weight (600#) forward, so now the rear axle load looks something like this:  1000 + 800/4 = 1200#
 

Carl L

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RV Roamer said:
Carl,
Is it not true that oversize spring bars would allow a greater percentage of the tongue weight to be transferred to the front axle?? I.e.., more than the 50% that we usually recommend?? ?If that is so, then you could compensate for other loads (payload in the bed) by tightening up the bars and transferring more of the tongue weight forward, thus reducing the overall load on the rear axle.

Example:
1000# of gear in the truck bed of a pick-up
800# trailer tongue weight
Rear axle load = 1000 + 800 = 1800# (without WD)

Now add a WD hitch with 1000# spring bars.? Tighten them up a bit and they should transfer 50% of the tongue weight (400#) forward to the front axle, so now the rear axle load looks like this:? ? 1000 + 800/2 = 1400#

Tighten up the bars a couple more notches and transfer 75% of the tongue weight (600#) forward, so now the rear axle load looks something like this:? ?1000 + 800/4 = 1200#

Well yeah maybe, but in my opinion that would be a seriously cockamamie way to do that.  Remember that your spring bars are working on the trailer frame as well as on the truck frame.  Hopefully, the trailer mfr balanced its frame with the weight of the trailer and the tongue weight and the spring bars one would use in connection with them.  Going to an excess of stiffness on the spring bars could have unfortunate results on the trailer A-frame -- especially in the light weight trailers.

Secondly, that whole procedure is by guess and by gosh.  The object of a WD hitch system is to restore the attitude and handling characteristics of the tow vehicle.  Without WD compensation the trailer tongue weight would put a truck in a tail down, oversteer condition.  I know, I used to haul uncompenstated lab trailers around California in connection with oil biz.  Even with big pickups, that was a no fun experience.  OTOH overcompensating sets up a nose heavy, understeer condition.  Steering tends to plow and you lighten up the drive wheels.    Trying to adjust that by chainlinks ... I just don't know.

Keep it simple.  Adjust your bars to the truck as has been described else where, and pay attention to your axle and GVCWR. 

 

ADubois

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Jul 27, 2005
Posts
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Thank you for the replies.
I think I should be fine with axle weight. I probably don't have more than 500-600 lbs in the back of the truck when towing. I've got a 1997 F350 CC 4x4 Powerstroke. It's GCWR is 20K lbs. My truck weighs in at 6600 lbs. Right now I've got an older trailer 79 Komfort travel trailer. Not real big its a 22ft but seems a little heavy. I've not had it weighed. I'm looking into a Wildcat 29BHS travel trailer that has a hitch weight of 820 lbs. a GVWR of 10980. I'm looking into an Equal-i-zer WDH setup. My options would be 800, 1000, or 1200 lbs for the WDH springs. So it seems from what I'm reading here I should look at the 1200 lb. springs. Does that sound right?

I know from past history it would be unlikely that I'll have the trailer to the GVWR. The brochure says its dry weight is 7280 lbs. and has a cargo capacity of 3221 lbs which equals 10,501. Not sure why it's cargo capacity any dry weight don't add up to the GVWR... but I don't see me adding 3000 lbs of cargo to the trailer. I realize water,  propane,  food, batteries, etc. all have weight I just don't see 3000 lbs. Just the same if I'm going to buy a WDH set up I want to get the proper one.

If I get that trailer I will simply need to load it up and have it weighed because if I did go over 10K lbs on the trailer it would be more than what my hitch is rated for. It says on it 10K with WDH.

On and on it goes...lol...
Thank you
Alan
 

Gary RV_Wizard

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I'm looking into a Wildcat 29BHS travel trailer that has a hitch weight of 820 lbs. a GVWR of 10980. I'm looking into an Equal-i-zer WDH setup. My options would be 800, 1000, or 1200 lbs for the WDH springs. So it seems from what I'm reading here I should look at the 1200 lb. springs. Does that sound right?

The hitch weight is usually given for the "dry" trailer, so it usually increases when loaded. How much depends on what is loaded and where.  At 820# of hitch (tongue) weight, the 1000# bars should be more than sufficient. You will want 10-12% of the total trailer weight on the hitch, so if you load her up to 9000#, then you will want to balance the weight to put 900-1000# on the hitch and then re-distribute that using the bars.  I still think 1000# bars would handle it, but 1200# would probably be OK too.  Most dealers will let you exchange the bars after trying them out, but be sure to ask. 

You don't need to drive around in it - you  level up the truck & trailer right in the driveway and use a tape measure to see how much the front and rear suspension on the truck are depressed.  You want the same amount front and rear, so the truck stays level after the trailer is hitched.  If you can't get front & rear the same without pulling up the spring bars to nearly their full tension, get bigger bars.  If the truck is level with almost no tension on the bars, get the next size smaller.
 

Lou Schneider

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Is it not true that oversize spring bars would allow a greater percentage of the tongue weight to be transferred to the front axle?? I.e.., more than the 50% that we usually recommend?? ?If that is so, then you could compensate for other loads (payload in the bed) by tightening up the bars and transferring more of the tongue weight forward, thus reducing the overall load on the rear axle.
You sure can.? In fact, back in the 70's, Trailer Life published an article where they hitched a front wheel drive Olds Toronado to a travel trailer using an equalizing hitch and a sway control bar.? ?They cinched both as tight as they would go, removed the rear tires from the Toronado and wired up the axle so it wouldn't drag on the ground.? Then they went for a drive on the Southern California freeways.

The only problems they reported were an excessively wide turning circle caused by the new longer wheelbase and being stopped by a Highway Patrol officer who was convinced they had to be doing something illegal.
 

Jim Dick

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Hi Lou,

I remember a TV ad for the Chevy front wheel drive car (can't remember the model) where they had a trailer hooked to the back with no rear wheels on the car! It was the strangest thing I had seen at the time. :)
 

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