WD Question For Ron

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Thanks, Ron.

Hope you, and yours, are having a great holiday wherever your travels have taken you. :)

Wes
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RinconVTR wrote:
---But the obvious reality, and the point behind the OP's question is the WDH transfers some weight allowing more payload. While a scale will tell you how far you can take this reality, its cheating in the minds of many.

Yes, the scale will tell you how much load has been transferred to the TT axles.

The WDH does not create or destroy weight -- it simply moves loads from one axle to another.
Load which is added to the TT axles can only come from the TV axles.

The TV's GVW is reduced, and there's no "cheating" involved.

Ron

Wes Tausend wrote:
Roughly speaking, I once believed the axle(s) of a very short trailer, with a lengthy TV, can approach absorbing 2/3's tongue weight, and even a moderate TT + long WB truck, about 1/2 the tongue weight to the TT axle, if both truck axle springs are compressed equally. But this doesn't seem to quite compute with Ron's formula above, if I got it right. It seems the distance from ball to front axle must come into play. I think Ron's formula is correct but may not be applicable to the this question.

Wes, if you are referring to the formula in this post, you need to be aware that formula is for the special case of returning the front axle to its unhitched load.

Your particular scenario, if I interpret correctly, pertains to how much of the "tongue weight" ends up on the front axle, rear axle, and TT axles after application of WD.
For this case, you first must calculate how much load is removed from or added to the various axles due to application of tongue weight.
Then you must calculate how much load is transferred to/from the axles due to application of WD.

Let:
Lf = Net load added to TV's front axle
Lr = Net load added to TV's rear axle
Ltt = Load transferred to TT's axles
D1 = TV's wheelbase
D2 = Distance from TV's rear axle to ball
D3 = Distance from ball to midpoint between TT's axles

For your condition of Ltt = (2/3)*TW,
Lf/TW = (2*D3-D2)/(3*D1)
Lr/TW = (D1+D2-2*D3)/(3*D1)

Picking some convenient example dimensions: D1=130", D2=65", and D3=195" gives --
Lf/TW = +83%
Lr/TW = -50%

If TW=900#, the net axle load changes are: 750# is added to the front axle,
450# is removed from the rear axle, and 600# is added to the TT axles.
And, you would need WD bars rated for about 2000# each.

If you changed D3 to 97.5" (a very short trailer), you could have 1/3 of the TW added to the front axle, zero added to the rear axle, and 2/3 of TW added to the TT axles.

Ron

jerem0621 wrote:
I use to do a lot of guessing too.

The real answer for You and Your rig is to go to a scale, get an unhitched weight, then get a trailer weight (that way you have actual numbers) then weigh the entire rig all hitched up. That will tell you how your weight is distributed.

Hope this helps

This is the only correct answer posted.

Keep in mind a tongue weight will be divided by 3 with a WDH, not two. You'll have the majority on the ball, some transferred to the trailer axles, and some transferred to the front TV axles. There is no way to know exactly how much actual weight is being transferred without using a scale.

Technically, you're suppose to add the actual tongue weight to the payload or other TV ratings like GVR. But the obvious reality, and the point behind the OP's question is the WDH transfers some weight allowing more payload. While a scale will tell you how far you can take this reality, its cheating in the minds of many.

TomG2 wrote:
You may want to PM Ron, if his is the only answer you are looking for. What you asked is not reality. One would not want to transfer all thousand pounds off the rear axle, even if it were possible.

I only mention the following because it seemed that several folks thought it was not possible.

Bob got his true question answered, so this is not important in that respect, but it is actually possible to remove all the 1000# tongue weight off the rear axle. Somewhere on the net is a picture of a front wheel drive car that (in constant danger of jack-knifing) was able to carefully move the rig with the rear wheels entirely dismounted from the vehicle. In that case the tongue weight, hitch weight and all of the previous non-hitched rear axle vehicle weight was removed from the rear axle by the WD bars.

In addition, at any time the rear axle fender-well height merely remains the same as prior to hitching, there is zero tongue weight on said rear axle. The front truck axle, now forced to share the total tongue weight with the TT axle(s), may be overloaded at that time, however. This situation also points out the danger of removing too much weight from the rear axle, in that traction, and vital steer-tracking, is then lost on a rear wheel drive as the weight on-axle becomes less and less.

I agree with Ron that any weight transferred to the trailer axle may be subtracted from the truck payload (keeping in mind the hitch weight).
I further add that this may bring a heavily loaded TV back within payload guidelines in some instances where it is barely overloaded prior.

Roughly speaking, I once believed the axle(s) of a very short trailer, with a lengthy TV, can approach absorbing 2/3's tongue weight, and even a moderate TT + long WB truck, about 1/2 the tongue weight to the TT axle, if both truck axle springs are compressed equally. But this doesn't seem to quite compute with Ron's formula above, if I got it right. It seems the distance from ball to front axle must come into play. I think Ron's formula is correct but may not be applicable to the this question.

Wes
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Tom, if you are going to qoute someone at least get the quote right. Here is exactly wat tho OP asked in his opening quesion and that i and several others answered. No need for him to come back and say that he got it.

Here is a copy/paste of his question.
Snip..."how much weight have you added to the payload of the truck besides the weight of the hitch? "
Barney

mrekim wrote:

TomG2 wrote:
What effect on payload would replacing 300 pounds of front axle weight have on payload?"

To get to max payload you need to load the truck so as to not overload either axle. A WD system will help in this regard by preventing the rear axle from being overloaded before max payload is achieved. This is done by returning some weight to the front axle and some back to the TT axles.

I know all that. The OP asked a specific question with regards to his situation.

TomG2 wrote:
What effect on payload would replacing 300 pounds of front axle weight have on payload?"

To get to max payload you need to load the truck so as to not overload either axle. A WD system will help in this regard by preventing the rear axle from being overloaded before max payload is achieved. This is done by returning some weight to the front axle and some back to the TT axles.

I did not see where the OP said that he "Got the answer". Maybe I missed it. "What effect on payload would replacing 300 pounds of front axle weight have on payload?" Sorry if I missed the answer.

APT wrote:
Did you get the answer you were looking for Bob?

Yep, he did. I answered it on page one in the 2nd and 3rd paragraphs of my post. In addition, Ron answered it a bit later in more detail.
Barney