Conflicting Advice: Payload

[DewTheDew]

Originally Posted by Mollysdad

I contend there's a difference between a trailer tongue weighing 1000# with a WD hitch vs. 1000# of gravel in the bed.
When the engineers came up with the payload, they didn't know which one you'd be carrying.
A WD hitch takes some of that weight off the hitch and transfers it to the front axle of the truck and the axles of the trailer. (If it didn't the sag would remain the same!)
So I think it's more complicated than simply adding tongue weight and passengers and equipment.
Where the payload doesn't transfer is braking. You still have to stop in a reasonable distance. Trailer brakes help, but mass is mass.

I think the difference you are discussing is taken into account by axle ratings. So perhaps your payload is 1500 lbs but if putting 1200 pounds of gravel into the bed of the truck brings you up to the rear axle rating then 1200 pounds is your effective maximum in that scenario. And this is where I was with my F150 and 27' AS; being well distributed I was approaching the limits of my front and rear axles simultaneously with the limits of the overall maximum GVWR of the truck (which is really what counts; the payload number has some variables in it).

And yes, mass is mass when it comes to braking but weight distribution helps, as do trailer brakes (it adds a frictional drag to the braking on the four extra tires for my AS).

[Dennis C]

This is an interesting discussion, but it feels to me like it’s getting unnecessarily complicated. Payload capacity is calculated by subtracting your truck’s curb weight from the Gross Vehicle Weight Rating (GVWR). Trucks with many options (4x4, sunroof, etc.) have a higher curb weight than trucks with fewer options, and therefore a lower payload capacity, assuming the GVWR is equal.

GVWR is set by the manufacturer, and it generally reflects the component in the vehicle with the lowest weight rating. This is typically the weight rating of the axles or tires.

The use of a weight distribution hitch doesn’t change the payload capacity at all, it simply transfers some of the weight from the rear axle to the front axle. Payload ratings for trucks don’t specify how or where the load is placed in the vehicle, they only specify the total payload. If you use a WDH, you’re actually reducing your payload capacity as mentioned above because most WDH systems are quite heavy. Mine weighs 79 lbs. The benefits of the WDH are: improved handling and stability, improved steering, and improved braking because of better load distribution to the front axle.

One thing that confuses this discussion is the fact that manufacturers often publish different maximum tongue weight limits to reflect the use of a WDH. For example, my truck has a 700 lb. tongue weight limit without a WDH, but a 1,250 lb. tongue weight limit with a WDH. This doesn’t mean that the WDH magically adds 550 lbs. of payload capacity, It simply allows for a heavier trailer tongue weight because some of that weight shifts to the front axle.

There are some folks who are comfortable exceeding their vehicle’s published GVWR if they are below the maximum axle rating for each axle. For example, my truck’s axle rating (front and rear) is 3,950 lbs. In theory, my truck could be loaded and balanced in such a way that I put 3,900 lbs. on each axle, for a gross vehicle weight of 7,800 lbs. This would be a scenario where I’m below the maximum axle weight limits for my vehicle, but I’m exceeding my vehicle’s GVWR of 7,200 lbs. by 600 lbs. Personally, I’m not comfortable with this scenario.

Good luck with your research on this topic. It can get confusing and it’s sometimes hard to find the information you need, but it’s out there.

[Seanlb]

Originally Posted by ROBERT CROSS

With a fallacy?...😂

The AS is 'swaying' and your "mines bigger" doesn't feel anything until it's on its side.

A big TV does nothing to prevent sway.

Bob
🇺🇸

Apologies Bob,

But your suggestion of 6-10” is a seriously dangerous idea.

Even if your vehicle has 6-10” of suspension travel, any pair of roadworthy shocks would soak that kind of moment up.

I just don’t understand the thinking that you’re eluding to. Perhaps I’m missing something...

[Collyn]

Originally Posted by ROBERT CROSS

With a fallacy?...��

The AS is 'swaying' and your "mines bigger" doesn't feel anything until it's on its side.

A big TV does nothing to prevent sway.

Bob
����

This only partially true: it increases the speed at which sway (caused by an overhung hitch) is likely to occur.

(Do not American read their own experts on this - that stem from the 1980s?) People here are pointlessly arguing about issues totally proven and known over 40 years ago.

Collyn

(ex General Motors [UK] research engineer).

[Collyn]

Originally Posted by ROBERT CROSS

With a fallacy?...😂

The AS is 'swaying' and your "mines bigger" doesn't feel anything until it's on its side.

A big TV does nothing to prevent sway.

Bob
🇺🇸

Tow vehicle mass does, however, increase the speed at which sway tends too occur. There is ample data re this from work done (in the USA) that shows various correlations.

Collyn

[Collyn]

Originally Posted by ROBERT CROSS

With a fallacy?...😂

The AS is 'swaying' and your "mines bigger" doesn't feel anything until it's on its side.

A big TV does nothing to prevent sway.

Bob
🇺🇸

I feel that in attempting to make your point, your 'A big TV does nothing to prevent sway' may mislead.

While true, a long wheelbase and heavy TV is likely to need to interact with the trailer at a higher speed before sway occurs.

For many correctly-laden US travel trailer combinations, the probable sway speed (sans anti-sway gear) is around 60 mph.

As I have noted in another post all of this was realized and quantified in the USA in the 1970s.

Collyn