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ajriding's avatar
ajriding
Explorer II
May 14, 2021

Tongue Weights weighed

I finally weighed.
Someone said something about having no WD hitch and the rear axle as a fulcrum unweighting the front axle, so I did math. I weighed my small trailer only so far.

I weighed about 350 lbs tongue weight. Not a lot.
the distance from rear axle to ball.
the distance from front axle to rear axle.

I divided the wheel base by the distance from rear axle to ball and got about 2.8 then divided that into the 350 lbs to get a number that I think represents the upward lift on the front axle.

So, 350 lbs pushing down on the ball will push up the front axle about 125 lbs (unweight the front end by 125 lbs).
This does not seem like much.
If you made a teeter-totter with similar distances and put 350 on the short end and 125 on the other then it would balance equally.

Add that I will have a small genny hanging from the front receiver hitch (50 lbs) cantilevered out which will multiply its weight slightly too, but I do not always have it.

So, with no WDH I am unloading the front end by 125 lbs at worst. Hit some bumps and I still do not think it will matter much.

Figure the motor and trans are at the front, so Im wondering how much weight will it take to create a situation where steering and unweighted front axle makes a safety concern.

I added airbags so that I can ditch the WDH as tired of removing WD bars for the last few miles of a trip up messy dirt roads, so I ran the numbers...
Im late for work now, so sorry if I explained it not-the-best...

Anyone else run similar numbers?
  • ajriding wrote:
    I finally weighed.
    Someone said something about having no WD hitch and the rear axle as a fulcrum unweighting the front axle, so I did math. I weighed my small trailer only so far.

    I weighed about 350 lbs tongue weight. Not a lot.

    Anyone else run similar numbers?

    The tongue weight on my trailer, when loaded, is always about 1350 lbs. I have a scale and that's what I want it to be when towing.

    So, it's similar.

    Except for the 1.
  • 350lb tongue weight as you pointed out may need some help with a compact truck.
    350lb will not make the truck unsafe to drive though with respect to weight off the front axle although it may be noticeable.
    These are the questions you can answer by yourself much better though. Have you not driven it to see how it feels?
  • So maybe I confused what truck you have.
    Yes, there is an unnecessary and weird stigma around wdhs / sway control and RVers.
    Yes it’s necessary in some scenarios but use your noggin and look At ALL the other trucks and trailers you see out there.
    Then you’ll understand there is a weird brain washing about wdhs in the RV community.
  • I am really wondering more for the sake that I hear on here so often people demand we run a WDH. One big reason for their demand is the "unweighting of the front axle". I ran quick numbers and do not see it for a small or medium trailer, even for 600 lbs, which might only translate to 200-250 lbs unweighted off the front.
    The bigger the truck the bigger and heavier the motor and trans too.

    My current truck is a Frontier with 4WD, not to be confused with WD.
    So the number are small compared to my 3/4 ton truck, but this "small" amt of weight does sag the rear quite a bit. I was surprised that the tongue was only 350lbs given the sag. Conclusion, I do need either WDH or bags. Sag cannot be. Running the WDH makes the truck drive and ride a lot better for sure.

    I might weigh again just to double check everything but dont expect numbers to be much different if at all. I was surprised at the low weight bc everything is in front of the axle - AC, batteries, electrical, solar, water tanks, sink, kitchen, fridge, propane... The couch and cabinet do straddle the axle and I keep the spare at the back, but thats about it.

    So, there ya go. If you ever thought 350 did not warrant a WDH now you know it does on some trucks at least. I even used it on the big 3/4 ton long bed with same trailer loaded more evenly. It just rode better with WDH. Makes me think I gotta have the weight wrong.....

    Also, affect and effect is worth researching.
  • You were running a wdh on a 350lb tongue weight trailer behind your camper rig? Seems odd 350lbs made the difference between needing to bag it or not...
    Regardless of the numbers your just ran (a fairly simple moment diagram), which are basically correct, assuming a level truck and a static situation, idk why you would have even contemplated a wdh ever with a little trailer like that.
    So good news, is it's not needed either practically or quantitatively.

    Regarding amount of weight on hitch before being needed. "If" you follow your hitch ratings on the truck and it's the old OE hitch on an early superduty, it likely a class IV with 1000lb weight carrying rating. (Haven't had an OG Superduty in many moons though, so going off memory)
    How much weight off the front is ok?
    Off the top, your 7.3 is 400+ lbs heavier than a 5.4 Triton, so the first 400lbs is free, lol.
    Next, presuming you haven't ever driven a truck that was light in steering from being overloaded, I'd "guess" you might start noticing it after another 500lbs comes off.
    Add them up, comfortably, you can take alot of weight off the front of a big truck, especially a diesel before it gets "light."

    Good news is, many people are convinced every day that they need a wdh, whether they do or not, so selling it on Craigslist should be a snap!
  • Truth is 350lb is with in the capacity rating to not need a WDH. You would only need a WDH once you get past 500lb if you have a 1500 series truck. Most 1500 series trucks have a 500lb weight carrying limit on the hitch. So once you get past 500lb of tongue weight, you are not only unloading the front axle, you are over stressing the hitch itself. at that point you need a wdh.

    Of course the weight at which you need a WDH is based on the weight carrying capacity of your receiver hitch. 2500 series, and 3500 many have a higher weight carrying capacity.

    My F150 has a weight carrying capacity of 500lb on the receiver, and a WDH tongue weight capacity of 1050lb.
  • Another thing to add to formula, if you already have say a camper, golf car, load of wood in the bed, the bed is already level to a bit lower than front, the formula does take into account the amount removed from FA by bed cargo.
    I took off close to 1000 lbs off the fa of my transit van last week with a 4500 lb pallet, I could not get over or in front of the RA. I have one of those with a 4' body extension on that back. So that WHOLE 4500 lbs was removing eight from the FA.
    Their is more to this than a simple formula.

    Marty
  • You forgot some things, as Ron Gratz has in his formula.
    Initially you are rear high. That first 100 lbs will not remove as much as formula says. Untill you squat to level, formula is on higher than actual. Once you go tail low, the formula is not taking enough off the FA.
    Also, depending upon you rear spring capacity, 350 lbs will effect the springs on my GM 1500, assuming same WB, more than a typical 25, which is effected more than a SW 3500, assuming different spring packs, which is effected more than a de 35, which is effected more than my class 6 Navistar
    My equipment trailer with 1500-1600 kids of HW, took 300-400 lbs off the FA of my SW 3500 with 6400 lb rear springs. I only lost 200 when I changed out springs to 8500, same loss as my 05 DW at 200-300 lbs. My Navistar with a 16500 spring pack, loses 60-100 lbs.
    My TT with 600-700 lbs of HW list all of 60-100 lbs with the TT with 6400 lb springs.
    So in a simple nutshell, no I have not gotten similar numbers for reasons given above in reality.

    Marty

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