Real World Capability
 

I have an idea. Let’s pretend for a moment that trucks are not assigned Gross Vehicle Weight Ratings to place them into specific classifications. That means there is no payload sticker. We are responsible for determining the true capability of our trucks based on the components that they come equipped with. I am asking to have a discussion based on logic (or possibly science) and the published ratings of individual components. That means the weight (sticker) police may need to suspend their version of reality if they wish to have meaningful input. I am not an expert in this subject but do tend to think through things in a logical manner. Obviously, I am using my F250 as the example. At this point it is completely stock.

The tires are rated at 3,750 pounds. That is 7,500 lbs. per axle. The front axle is rated at 5,600 lbs. Actually, that’s the rating for the coil springs but Ford applies the same rating to the axle. I can’t think of any reason why that shouldn’t be the maximum load placed on the front end. One could install stiffer springs to add additional load carrying capability and the axle would clearly support it.

For the rear, the combined load capacity of the tires is also 7,500 lbs. The rear axle rating is 6,340 pounds. As currently equipped, based on the ratings of the individual components, my truck should be capable of supporting a gross vehicle weight of 11,940 pounds as long as the front does not exceed 5,600 lbs. and the rear does not exceed 6,340 lbs. That strikes me as sound logic but maybe I’m missing something.

Here is where I could start some trouble. The rear axle is clearly de-rated in my truck. I have the same Dana axle as a SRW F350 but in that application, the axle is rated at 7,230 lbs. My rear leaf springs are not the same as the F350 so for this discussion, let's assume that's the limiting factor. Correct me if I’m wrong, but wouldn’t air bags change the equation? Don’t airbags allow some of the weight in the rear to bypass the leaf springs (the weak link in the equation) and transfer it directly to the axle? Since we have already established that the Dana axle is capable of supporting 7,230 pounds in the F350, why would it be any less capable in a F250? With a set of airbags installed, why wouldn’t my truck be fully capable of carrying 7230 on the rear axle just like an F350?

I’m not asking about what is “legal”. I am trying to logically determine the true capability of my truck. I’m also not suggesting that any ratings or capacities should be arbitrarily disregarded. In all things, I am of the mind that the applicable information should be gathered and processed, then the derived insight can be used to make an educated decision.

Your logic does make sense, but not to the commisioners of revenue. Hence, the GVWR system in place. Here in VA, annual personal property taxes are discounted more than 40% if your GVWR is 10,000# or less. My F250 is capable of more (I have Torque air-bags), but my vehicle's documented pedigree states 10,000# GVWR. To exceed that is my personal gamble with the tax man.

PS - I had a big red V10 Excursion.

This has been hashed over and over but I'll try to answer your question as concisely has possible. Others will answer and say differently but if you care to look up the governing laws you will find the same as I state here....

You have nailed the difference between your 250 and a 350, it is the rear leaf spring pack. A 250 is made and marketed for a smooth ride, those of us that know and actually use our trucks pay the little bit of extra and get the 350. The market demands a 250 and Ford is happy to supply. I would presume that you have purchased a 250 then did the numbers research after the fact....

The DOT looks at the axle ratings and combines them for the total weight allowed. A trailer, if added, gets its own axle ratings and is added as another vehicle. The DOT is the authority having jurisdiction in the USA. Ford puts their number on their axles and that is what the DOT uses, end of story.

No matter what others will tell you, you can change the rating that come "sticker-ed" from the factory. Companies that will are few and far between, but exist, they will apply a new sticker to what ever they engineer or approve, then this is what the DOT will be reading on the side of the road. This boils down to the company taking the risk and standing behind their decision. A company has much more weight than an individual in court in the event anything occurs i.e. road accidents. You doing any jackleg modification yourself will be seen as such in court. For the vast majority of us the simplest solution is to buy a truck with the rating required.

To possibly answer your, or one of your, questions: Adding airbags only changes the ride height not actual load bearing capability. The weight, and forces exerted, are still borne by the leaf springs and the supporting system. There are other directional forces placed on the system besides vertical ones....

Adding the two GAWR together to come up with a new GVWR number isn't logical. Almost every bit of cargo added to the vehicle is going to be biased toward the rear axle, not the front axle.

Logic is there, but If you were to get a ticket for what is deemed overweight or goig too fast for the load it'll be "tell it to the judge."
but your logic makes sense.

I actually knew exactly what I was getting with the F250. Although it is my personal truck, my employer gives me a generous vehicle allowance monthly and requires that I list them as an additional interested party on my insurance. Because of that, they have some stipulations. One of them is no class 3 vehicles because that would make the truck subject to certain DOT regulations that the company and I would need to abide by. They aren't interested in the additional liability. So, I definitely wanted an F350 (and tried to get them to make an exception) but had to special order my F250 with the High Capacity Trailer Tow Package. That makes it identical to an F350 with one less leaf in the rear. At this point, I simply need to determine what this truck is actually capable of and what I am comfortable with.

I'm in VA also and did a little research before ordering my F350. If the discount in personal property taxes you mentioned is the personal property car tax relief act, it is for a gross vehicle weight of 10,000 lbs or less and not the weight rating.(GVWR). https://taxes.arlingtonva.us/vehicles/tax-relief/

As I stated "my truck should be capable of supporting a gross vehicle weight of 11,940 pounds as long as the front does not exceed 5,600 lbs. and the rear does not exceed 6,340 lbs". The point of the post was to look at the ratings of the individual components and not exceed those.

I do apologize for staring yet another weight thread. I know it has been rehashed a million times and I have participated in a few. My intent was to have one that didn't inevitably devolve into the GVWR/payload sticker camp vs. the do whatever you want camp. I really wanted it to be a little more logic and data based.

That website said, "A passenger car, motorcycle, pickup truck or panel truck that has a registered gross weight of less than 7,501 lbs. Effective tax year 2016, pickup trucks registered for personal use and weighing 7,501 pounds but not in excess of 10,000 pounds may qualify for tax relief." In 2016, the upper GVWR limit was raised from 7,500# to 10,000#. When I bought my first Excursion in 2003, I asked the DMV to lower the stated GVWR (it was over 7,500#) on the reistration so I could get the tax relief. Are you saying your GVWR on your registration is over 10,000# and you get PPT relief?

The front Dana60 itself is rated at 6000lb, according to Ford. The only difference between that max rating and the lower sticker values is the front coil springs.

Also, the brakes are the same as the F350 as well.

So, real-world, I think there are no inherent safety issues hidden by your logic.

My understanding from talking with DOT, is that as far as they are concerned, your GVWR is 11,940. He said as long as no components rating is exceeded, your good (exception is 20k max per axle). Your tow rating is the GCWR or the GVWR of the truck + GVWR of the trailer, whichever is greater.

I understand where you're going with it. In my opinion, the airbags take some of the stress off the leaf spring hangers (where the springs attach to the frame). But just because you've spread the weight doesn't mean all the components involved can handle more. Sure, there's an engineering fudge factor involved somewhere but we don't know what it is. So trying to take that into account is like hitting a moving target.

I broke a leaf spring bracket on my prior truck thinking there was more capacity than was published. I learned my lesson there and I'll be sure to keep within the published maximums on my F-350.

I see a lot of this argument by guys with F-250's trying to justify their purchase when they could have easily moved up to an F-350 for not much more. I understand your situation the way you explained it. You're stuck with the lower capacity because of it. It's something you just have to live with now.

I don't have my registration yet as my truck is on order. Registrations I have for current and former vehicles only list the empty weight (EW on the registration). The gross weight (GVW) is the weight of the truck empty. The gross vehicle weight rating (GVWR) is the weight of the truck plus payload. I think you are getting the two confused.