Forum Discussion

rbpru's avatar
rbpru
Explorer II
Apr 21, 2014

WD hitch specifics

We know that if I added another set of springs to my F-150 I could stiffen the suspension and increase the tongue weight. There is a limit of course because the remainder of the system, the bearings, brakes, frame etc. remains the same.

Ford says the use of a WD hitch increases my particular truck’s max trailer weight from 5000 lbs. to 9800 lbs. hence the permissible tongue weight would rise from 500 lbs. to 980 lbs. In effect by adding two torsion bars I have stiffened the suspension shifting some of the weight to the front axle and a portion of the weight to the TT.

The question is, do the torsion bars increase the vehicles “max cargo weight” by any more than the amount transferred to the TT?

From what I understand it does not, max cargo is max cargo.

I am also curious as to what percentage is transferred to the TT.
  • fla-gypsy's avatar
    fla-gypsy
    Explorer
    Apr 21, 2014
    No you cannot increase the payload but you may reduce the amount of weight on the truck slightly. The amount will vary depending on the amount transferred. The only way to know for sure is to weigh it with WD and without it.
  • brulaz's avatar
    brulaz
    Explorer
    Apr 21, 2014
    rbpru wrote:
    We know that if I added another set of springs to my F-150 I could stiffen the suspension and increase the tongue weight.

    I wouldn't say you can increase the tongue weight that way, at least not "Officially". You would improve the truck's handling of that increased tongue weight though.

    There is a limit of course because the remainder of the system, the bearings, brakes, frame etc. remains the same.

    Yup.

    Ford says the use of a WD hitch increases my particular truck’s max trailer weight from 5000 lbs. to 9800 lbs. hence the permissible tongue weight would rise from 500 lbs. to 980 lbs. In effect by adding two torsion bars I have stiffened the suspension shifting some of the weight to the front axle and a portion of the weight to the TT.

    I don't think it "in effect" stiffens the suspension. It just transfers weight from the rear axle. This better balances the weight on the truck's two axles improving the ride. You could well want a stiffer suspension with a WDH, at least I did. IMHO the stock F150 suspension is stupid soft, only good for unloaded driving.

    The question is, do the torsion bars increase the vehicles “max cargo weight” by any more than the amount transferred to the TT?

    From what I understand it does not, max cargo is max cargo.

    Yup.

    I am also curious as to what percentage is transferred to the TT.

    In my case only about 12% of TW, but I believe that Ron Gratz has said 20% on average. So I guess "it depends".

  • wmoses's avatar
    wmoses
    Explorer
    Apr 21, 2014
    rbpru wrote:
    The question is, do the torsion bars increase the vehicles “max cargo weight” by any more than the amount transferred to the TT?

    When the spring bars are connected, weight seen by the hitch is decreased as load is transferred to the other axles - truck and trailer. This means that the truck rear axle will see some lightening and the front axle will see some increase. It also means that you should then be able to dump more load into the bed of the truck to bring it up to the axle rating, providing the spring bars and all other components (including trailer axle) are not overloaded. So the answer is YES.

    The amount of "increase"can only be determined using a scale, and is not just the amount transferred one way (i.e. to the TT).
  • Ron_Gratz's avatar
    Ron_Gratz
    Explorer
    Apr 21, 2014
    brulaz wrote:
    In my case only about 12% of TW, but I believe that Ron Gratz has said 20% on average. So I guess "it depends".
    Yes, I usually say -- When using a WDH to return the front axle load to its unhitched weight, the vertical load imposed by the TT will be equal to about 80% of the TT's tongue weight.

    The amount of load transferred to the TT's axles is directly proportional to the amount of load added back onto the TV's front axle.

    Depending on TV and TT dimensions --
    for each 100# transferred to the TT's axles, you will have restored about 200-250# to the TV's front axle,
    and will have removed about 300-350# from the rear axle.

    Ron
  • skipnchar's avatar
    skipnchar
    Explorer
    Apr 21, 2014
    When you prop up the rear with helper springs or air bags it doesn't transfer ANY addition weight to the front axle which is the problem with those fixes. A properly sized (sized for 15% of the trailers GVWR) and properoly adjusted WD system will allow the maximum rated tongue weight to be carried but will NEVER have any effect on the trucks GVWR or AXLE ratings except that they will both be reduced by the weight of the hitch itself. It is absolutely the BEST way to distribute the load and maximize your towing capability.

    Good luck / Skip
  • APT's avatar
    APT
    Explorer
    Apr 21, 2014
    When you restore 100% of front axle weight to unhitched weight, most people on here report about 20% goes to TT axles. But Ford recommends only restoring half of the lost weight on 2011+ F150s, so the 12% seems more realistic. So that means you effectively have an additional 12-20% of TW available as payload.

    Honestly, I would not worry about 100-200 pounds. The truck should handle well at GVWR, slightly over even. If you are the type of person who is going to wprry about that kind of weight, get a bigger truck.
  • Bob_Landry's avatar
    Bob_Landry
    Explorer
    Apr 21, 2014
    skipnchar wrote:
    When you prop up the rear with helper springs or air bags it doesn't transfer ANY addition weight to the front axle which is the problem with those fixes. A properly sized (sized for 15% of the trailers GVWR) and properoly adjusted WD system will allow the maximum rated tongue weight to be carried but will NEVER have any effect on the trucks GVWR or AXLE ratings except that they will both be reduced by the weight of the hitch itself. It is absolutely the BEST way to distribute the load and maximize your towing capability.

    Good luck / Skip


    You are correct in that it does not change any of the trucks ratings, but it does change the amount of weight transferred to the front axle. It actually decreases the weight transfer. The reason is that by raising the height of the truck's rear, you are effectively tilting the hitch towards the truck and that reduces the tension on the bars and the weight transfer. That's why the WD needs to be readjusted with the truck and trailer loaded after installing bags or helper springs.
  • brulaz's avatar
    brulaz
    Explorer
    Apr 21, 2014
    skipnchar wrote:
    When you prop up the rear with helper springs or air bags it doesn't transfer ANY addition weight to the front axle which is the problem with those fixes.
    ...


    I've been telling this to people for years, and somehow it seems to be a real hard concept to grasp. They seem to think that a small change in tilt will move a lot of weight around.

    Has anybody taken their loaded truck with adjustable air bags and weighed front and rear axles with the bags inflated and not, and presented that data somewhere on the internet? Would love to point people to it (Assuming it supports the "no or little change" hypothesis of course;)).

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