WD impact on payload

[steilkurve]

Hey all. Reading up on the effects of weight distribution as I plan a potential rig upgrade and I’m confused... When I weigh my current rig before and after applying weight distribution, I clearly seen weight moving from the rear TV axle to the the front TV axle and the TT axle. Therefore, the total load applied to my TV is getting reduced. Yet, I’ve seen many posts where folks say that the full tongue weight is still applied to the TV with WD. How can that be if I actually see weight move away from the TV to the TT when WD is engaged? Thanks in advance for enlightening me!

[Andrew T]

You have it correct, payload really does not relate to towing, it is a number for a solo vehicle.
With 1000 pounds of hitch weight if you move 300 to the front axle and 300 to the trailer you are actually only using 400 pounds of the payload for hitch weight. The manufacturer does not know you can add weight to the front wheels. A better number to look at is to weigh your loaded combination and make sure you are not drastically overloading an axle capacity.

The only way many of the factory tow ratings are possible is by using this method.

If you like send me an email I have a column on this I can send you with it all laid out andy@canamrv.ca

[B. Cole]

If trying to move weight around,to help keep your front steer tires down, you need a much larger tow vehicle.
With a too small of a tow vehicle, your trailer is able to drive the tow vehicle.

[steilkurve]

Originally Posted by Andrew T

You have it correct, payload really does not relate to towing, it is a number for a solo vehicle.
With 1000 pounds of hitch weight if you move 300 to the front axle and 300 to the trailer you are actually only using 400 pounds of the payload for hitch weight. The manufacturer does not know you can add weight to the front wheels. A better number to look at is to weigh your loaded combination and make sure you are not drastically overloading an axle capacity.

The only way many of the factory tow ratings are possible is by using this method.

If you like send me an email I have a column on this I can send you with it all laid out andy@canamrv.ca

Thanks Andy. That's helpful. Sent you an email for that column. Appreciate it.

[JEB]

Originally Posted by steilkurve

Hey all. Reading up on the effects of weight distribution as I plan a potential rig upgrade and I’m confused... When I weigh my current rig before and after applying weight distribution, I clearly seen weight moving from the rear TV axle to the the front TV axle and the TT axle. Therefore, the total load applied to my TV is getting reduced. Yet, I’ve seen many posts where folks say that the full tongue weight is still applied to the TV with WD. How can that be if I actually see weight move away from the TV to the TT when WD is engaged? Thanks in advance for enlightening me!

A WDH definitely does reduce the amount of the tongue weight that counts as payload to the extent weight is transferred from the tow vehicle’s rear axle to the trailer axle(s). The portion that is transferred to the front axle still counts as payload because it stays with the truck and contributes to its overall GVW. Where you might be getting confused is compliance with hitch ratings. You measure tongue weight for this purpose by disengaging the WDH and measuring the static dead weight on the hitch. So, to sum up, tongue weight for payload/GVWR purposes is what stays with the truck after weight distribution is applied. Tongue weight for hitch rating purposes is the static, dead weight on the hitch before weight distribution is applied. You need to look at both to make sure you are overloading neither the truck nor the hitch, each of which has its own ratings.

[steilkurve]

Originally Posted by JEB

A WDH definitely does reduce the amount of the tongue weight that counts as payload to the extent weight is transferred from the tow vehicle’s rear axle to the trailer axle(s). The portion that is transferred to the front axle still counts as payload because it stays with the truck and contributes to its overall GVW. Where you might be getting confused is compliance with hitch ratings. You measure tongue weight for this purpose by disengaging the WDH and measuring the static dead weight on the hitch. So, to sum up, tongue weight for payload/GVWR purposes is what stays with the truck after weight distribution is applied. Tongue weight for hitch rating purposes is the static, dead weight on the hitch before weight distribution is applied. You need to look at both to make sure you are overloading neither the truck nor the hitch, each of which has its own ratings.

You are correct and I get that. One shouldn't go beyond the hitch rating even if they are still within acceptable payload limits. What really got me confused is some posts suggesting that you should account for the full tongue weight in your payload calculation which was contradicting the evidence I gathered while weighing my rig.

[1StreamDream]

Just adding a little to what JEB said ... and emphasizing what other posts have reminded in that payload rating is just one aspect, and it can be confusing, I caution you to take the time needed to keep studying, and get comfortable and famiiar with all of it. Payload is one of the key numbers. Individual axle load rating is another critical number. Hitch rating is another critical number. Agree with all others that point out that WD can remove *some* weight from the tow vehicle rear axle, and that some of that moved weight does go rearward to the trailer axle, thus the payload becomes slightly reduced on the tow vehicle. As far as hard numbers, this is very difficult to try and generalize (I think) and the only safe thing to do is get numbers from a weight scale to confirm. Even when you get those, every time you load your truck and trailer, those numbers will vary a little bit, so always keep that in mind. In my real world experience, I had a situation where I was well under the payload rating of my vehicle (F-150) but I was OVERLOADED on my rear axle. This is a real situation, it can happen, and it happened to me so this is why I emphasize take your time and get familiar with these numbers and how they impact you. Your post to ask for info here is a great start, I have learned a great deal from others here with more experience than I have. I always try to stay on the conservative side when it comes to things like this, as they really can be direct impacts to safety of you and others around you. Best of luck on your journey.

[JEB]

Originally Posted by steilkurve

You are correct and I get that. One shouldn't go beyond the hitch rating even if they are still within acceptable payload limits. What really got me confused is some posts suggesting that you should account for the full tongue weight in your payload calculation which was contradicting the evidence I gathered while weighing my rig.

Yeah, that’s wrong. You can’t distribute weight without transferring it. And some of that transfer is offloading weight from the truck to the trailer. No doubt about that. The impact is not as much as some hope for—1/3 of the tongue weight would be a stretch—but there is some transfer.

[ROBERT CROSS]

As noted in post #2.

I gave up using 'payload' numbers years ago.🤔

If I'm under the TV & AS tire and axle load limits, have a proper lash-up and the grunt to move it's always worked very well for us.

Bob
🇺🇸

Our #'s

GAWR front 4180
Loaded for camping, 3740/ hitched, WD set 3640
GAWR rear 5500
Loaded for camping, 3600/ hitched, WD set 4680

E rated TV & AS tires

1200lb TW, scale

860lb receiver wt with WD set
560 to the FA
160 to the AS
720 moved

760lb off the TV front axle with no WD and a loaded for camping rig.
560lb returned to the FA with WD set, 100lb light
AS axles 7480lb with no WD, 7640lb with WD, 160lb moved.
560+160=720lb total weight moved, 1000# bars on a Hensley hitch and Reese V TowBeast.

Bob
🇺🇸

[JEB]

Originally Posted by ROBERT CROSS

If I'm under the TV & AS tire and axle load limits, have a proper lash-up and the grunt to move it's always worked very well for us.

Bob
🇺🇸

Problem with that method is that many tow vehicles have GVWRs lower than the sum of their GAWRs. If I loaded my front and rear axles to the max, I’d exceed the GVWR by 700 lbs. Keeping an eye on payload helps ensure that you don’t exceed the latter.

[jcl]

Originally Posted by JEB

Problem with that method is that many tow vehicles have GVWRs lower than the sum of their GAWRs. If I loaded my front and rear axles to the max, I’d exceed the GVWR by 700 lbs. Keeping an eye on payload helps ensure that you don’t exceed the latter.

Are you concerned about exceeding your GVWR by that amount, if you meet the other limits?

It doesn’t cause you to exceed tow vehicle power or braking design targets.

It isn’t likely to physically break anything, since the structural limits are addressed by the axle ratings.

It may impact you if you are a commercial carrier, but those regulations are tied to vehicle and operator licensing, and tax rates, as much as anything.

[JEB]

Originally Posted by jcl

Are you concerned about exceeding your GVWR by that amount, if you meet the other limits?

It doesn’t cause you to exceed tow vehicle power or braking design targets.

It isn’t likely to physically break anything, since the structural limits are addressed by the axle ratings.

It may impact you if you are a commercial carrier, but those regulations are tied to vehicle and operator licensing, and tax rates, as much as anything.

I am concerned about American tort lawyers were I ever to be involved in an accident where I was towing in excess of the manufacturer’s specifications.

[Dennis C]

Payload limit is calculated by subtracting your vehicle's curb weight from the Gross Vehicle Weight Rating (GVRW). It's that simple. If you distribute some of the weight from the rear axle to the front axle, it has zero impact on this calculation.

Think of it with this crude analogy: If a person is strong enough to carry a maximum of 40 lbs. of weight when walking, it's much easier to carry 20 lbs. of weight in each hand as opposed to 40 lbs. of weight in one hand. Splitting it up balances the load better, but that person can still only carry 40 lbs. of weight. That person can walk better, they are better balanced with the weight spread over both hands, etc., but their maximum limit doesn't change when they redistribute the weight.

GVWR is determined by the manufacturer of the tow vehicle, taking many things into consideration. One of those things is the "weakest link" in the system in terms of weight capacity, which it typically the axles or the tires.

As mentioned above, it is possible to exceed the GVWR of a tow vehicle while still remaining below the weight limit for each axle or the tires on that axle. Many people are comfortable with this scenario, and are therefore willing to exceed the published payload ratings as long as they are underneath the individual axle or tire ratings because of a weight distribution hitch. Personally I am not one of those people, but some others have no issue with it.

As a practical example, my truck's maximum tongue weight limit without a weight distribution hitch is 700 lbs. With a weight distribution hitch, the maximum tongue weight limit goes up to 1,250 lbs. The weight distribution hitch doesn't magically add 550 lbs. of payload capacity, it simply shifts more of the weight to the front axle, which therefore allows for the use of a heavier tongue load. It has absolutely no impact on payload capacity, and in fact it adds weight, which slightly reduces payload capacity.

[Wazbro]

I like to use the full published tongue weight as an estimate of payload that will be used. Usually when loaded for a trip after weight distribution the tongue weight will take close to that much payload with an Airstream. At least close enough before going to scales to check.
Example: published tongue weight 838lbs loaded tongue weight 1050lbs transfer 212 lbs to trailer, back to 838lbs.

[ROBERT CROSS]

Originally Posted by JEB

Problem with that method is that many tow vehicles have GVWRs lower than the sum of their GAWRs. If I loaded my front and rear axles to the max, I’d exceed the GVWR by 700 lbs. Keeping an eye on payload helps ensure that you don’t exceed the latter.

That sounds like a TV problem, time to shop.

Has anyone lost a case because they were tested payload negative?
I doubt a non DOT case would even make it into the room.

Bob
🇺🇸

[JEB]

Originally Posted by ROBERT CROSS

That sounds like a TV problem, time to shop.

Has anyone lost a case because they were tested payload negative?
I doubt a non DOT case would even make it into the room.

Bob
🇺🇸

You want to be the test case? I don’t. If you have the education and experience to evaluate the risk of a case of this kind, I’m all ears.

[Adiredneck]

If you're that close to overloading your TV payload that WD is being figured into the equation, you need a TV with more payload.

[new2trailer]

There used to be an ad that showed a car without rear wheels pulling a trailer, to show the benefit that a weight distribution brings to towing.

I don't know the math behind it but it is a way to get more towing capacity out of a tow vehicle. I used a wd hitch with my Porsche to tow a 25 ft front bed to great advantage. It was pretty close to a match made in heaven. I used the hitch to move some onto the front axle. That balanced out the car and made the combo spectacular far better than the usual truck and trailer.

If you can stop in a respectable distance, I say you are good to go with your towing.

Mike

[azflycaster]

Originally Posted by new2trailer

There used to be an ad that showed a car without rear wheels pulling a trailer, to show the benefit that a weight distribution brings to towing.

I don't know the math behind it but it is a way to get more towing capacity out of a tow vehicle. I used a wd hitch with my Porsche to tow a 25 ft front bed to great advantage. It was pretty close to a match made in heaven. I used the hitch to move some onto the front axle. That balanced out the car and made the combo spectacular far better than the usual truck and trailer.

If you can stop in a respectable distance, I say you are good to go with your towing.
.

Mike

Here is a link to the thread with a picture
https://www.airforums.com/forums/f46...-wd-10753.html

[Collyn]

It is often overlooked that a vehicle maker 'towing capacity' is (in effect) what that vehicle can tow up a hill (and stop and restart). It rarely (if ever) relates to speed etc.

Collyn