Weight distributing hitch math?

I was sure that there was no free lunch. I was doing the mind game of where did the weight go. If the majority of the weight is transferred to the front axle, the remainder had to be transferred to the trailer.

We did pass on a few heavy weights because the dealer recommended a 3/4 ton TV.

rbpru wrote:
If I understand the numbers correctly, a WD hitch transfers about 25% of the ball weight back onto the TT axels and divides the remaining 75% more evenly between the front and rear axles of the TV.

Does this mean with 500 lbs. of tongue weight, I gain 125 lbs. more cargo capacity on the TV? And lose 125 lbs. of TT cargo capacity?

When you drop the coupler on the ball without using WD,
a load equal to about 40-50% of the tongue weight will be removed from the front axle, and
a load equal to about 140-150% of TW will be added to the rear axle.
The combined added load on the TV's front and rear axles will be equal to 100% of the tongue weight.

If you then adjust the WDH to restore all of the load removed from the TV's front axle,
a load equal to about 20-25% of TW will be transferred to the TT's axles.
A load equal to about 40-50% of TW will be added to the TV's front axle, and
a load equal to about 60-75% of TW will be removed from the TV's rear axle.

The net load change on the front axle due to TW and WD will be zero, and
the net load change on the rear axle will be an addition equal to about 75-80% of TW.
The net load change on the TV's axles will be an addition equal to about 75-80% of TW.

So, you are correct -- with a TW of 500#,
when the WDH is adjusted to transfer a load equal to 20-25% of TW to the TT's axles,
the load on the TT's axles will increase by about 100-125#, and
the load on the TV's axles will decrease by about 100-125#.

In compliance with the law of conservation of mass,
mass has been neither created nor destroyed by the WD process.

Ron

lbrjet wrote:
No, that is not how it works. Figure 15-25% of the tongue weight will be moved back to the trailer axles. The rest will be carried on the rear axle of the tow vehicle. There is weight moved to the front axle, but this is the same weight that moved from the front axle to the rear axle when the trailer was attached.

Yep!:)
Barney

No, that is not how it works. Figure 15-25% of the tongue weight will be moved back to the trailer axles. The rest will be carried on the rear axle of the tow vehicle. There is weight moved to the front axle, but this is the same weight that moved from the front axle to the rear axle when the trailer was attached.

Does this mean with 500 lbs. of tongue weight, I gain 125 lbs. more cargo capacity on the TV? And lose 125 lbs. of TT cargo capacity?

What you might gain is a little more tongue weight capacity that equates to a little heavier trailer figured at 13 percent of total trailer weight on the tongue. Maybe something near 1000 pounds heavier trailer would be a ball park figure. If you are so close on your payload that 125 pounds makes or breaks you; get a smaller trailer or a bigger tow vehicle.

rbpru wrote:
If I understand the numbers correctly, a WD hitch transfers about 25% of the ball weight back onto the TT axels and divides the remaining 75% more evenly between the front and rear axles of the TV.

Does this mean with 500 lbs. of tongue weight, I gain 125 lbs. more cargo capacity on the TV? And lose 125 lbs. of TT cargo capacity?

A WD hitch can easily use up close to 100 pounds of payload. There is no free lunch. Lots of information on this topic in the "Towing" forum. A whole sticky is devoted to it.

While the above post is correct when it comes to GVW, I do not believe that was your question. If you weighed your axles before and after what you suggest is correct accept I'd say most of the weight shift will be to the front axle with WD. The main reason for using WD is when there is too much weight on the rear axle. Also on a short TT the ratio could be closer to 50/50.

Nope, you don't gain anything from the rated weight limits of the two, you're just redistributing forces.