It makes sense because the minimum 15% allows them to reach a higher tow rating. If the truck could pass the test with 1700lbs of pin then the hdpp trucks would be rated higher but they’re not. You better believe that if Ford could up the “best in class” 5th wheel rating they would. They are in fact rated lower than EB max tow trucks for towing in 2018 ratings. The SAE test is a test of GCWR, how high can we go and still pass the test. A HDPP truck loaded to the max by itself doesn’t have to pass any SAE test so you load the axles and or Gvwr to the max and go at it. Add a trailer with understeer and sway requirements and a GCWR now becomes the limiting factor, not truck payload or RAWR.

 

The previous gen trucks fit what you posted. Current gen ('15+) trucks are almost all GCWR limited whether HDPP or not.

 

I don't know about "almost all" but GCWR is certainly more of a factor for the newer gen trucks than previously.

 

Ok, I think we might be getting somewhere now....

So you agree that GCWR is the limiter for hdpp towing capacity? After all, the whole purpose of the SAE test is to find the GCWR (with a standard test).


But here you are saying the pin weight is the limiter for the hdpp towing capacity. As stated, the purpose of the test is to find the GCWR, not the pin weight rating. Keeping the pin weight to only 15% will only help raise the GCWR if pin weight is truly the limiting factor. This typically means the RAWR or GVWR is hit first. Again, we have to data to support this being the limit. All data available points to this simply being the pin weight that was on the truck when it passed the test.

So what can limit pin weight? In the absence of a published pin weight limit, there are only 2 published numbers that can limit the pin weight, GVWR & RAWR. The truck is already built/engineered/tested to weight x pounds (GVWR) and have y pounds on the rear axle. Let's assume the rear axle has enough capacity remaining to put all additional weight in the bed, and get to the GVWR. Let's say this is 2500#s. We have data points in the payload thread to support this with the new model HDPP trucks. So, the truck is capable of handling 2500# in the bed. I think we can all agree on that. Now, the truck doesn't care if the weight comes from a load of dirt, or a trailer's kinpin, the physics are still the same. But if you put 2500# pin weight, and that's 15% of the trailer, you are at 16,667# trailer weight & GCW is over 21k#. The drivetrain can't handle this much weight. When you lower the trailer weight enough for the drivetrain can handle it (i.e. pass the test), you have reached the GCWR. Subtract out the weight of the truck (& required passengers, etc) and you have the tow rating. As long as AWRs and GCWR aren't exceeded, the pin weight is irrelevant.

 

On the hdpp trucks stand alone the CG of the load makes a big difference. Check the towing guide at the HDPP section and it states that CG position may derated capacity. So it does make the difference where all the weight is carried on the truck. Certainly you could go to 20% pin weight as long as the trailer weighs 7800 lbs.

 

Glad mass-hole mentioned the weight of the 5th wheel hitch itself because that's often overlooked.


Ford SHOULD maybe make more mention of all the things you need to take into consideration. However, if you actually look into it, all the information IS there. Between that info and some googling, you can easily find everything you need to know.


I wouldn't expect Ford to include things such as weight of the actual hitch ball/5th wheel hitch itself in the numbers because there are so many out there that have a wide range of weights. Now if they posted their tow and payload ratings without the hitch bracket with a fine print saying "Before hitch installation", THAT would be shady...

 

But pin weight and payload was not the limiting factor for the HDPP trucks in 2017. If we do the math you come in well below the stated payload of the HDPP trucks.

A 157" 2x4 3.5EB with HDPP has a stated 5th wheel towing capacity of 11,600 lbs and max payload of 2890 lbs. (.15*11,600 lb)+250 lb for the hitch + 300 lbs of passengers = 2290 lbs. They literally have 600 lbs more payload capacity even accounting for the hitch and passengers. GAWR also shouldnt be an issue. Seems a screw HDPP truck comes in around 2200-2300 lbs on the rear axle with a 4800 lb RAWR. They have 2500-2600 lbs of axle left so the rear axle alone could support the entire load of pin weigh, people and hitches but probably isnt.

something else limited GCWR and my guess is it was braking or handling performance which is why the 20" wheels allowed them to bump it up in 2018.

 

Yes it's legal. No agency has a data base of every vehicle manufacturers GCWR.

The federal sticker with the GVWR, and axle ratings are the only concern. Of course tire ratings and hitch rating can be looked at.

That payload sticker is for your information. By the time people put in a tool box, bigger tires and wheels, lift kits, brush guard and any other bolt on accessory that number is useless.

 

The more I look at the ratings I’m more convinced that what he said was right. You cant use the GAWR and GVWR the HDPP has and apply it to increase the tow ratings. The way I look at it if you increase pin weight over the 15% of the max tow weight rating you are increasing the ratings. You could probably push a pin weight a small amo7nt higher with a reduced trailer weight and stay under GCWR. Does anyone on the forum tow a fifth wheel with 1300-1500lbs of pin weight with a HDPP truck and not use any rear suspension enhancement? I would be interested in seeing a picture of how it handles the weight.

Just a FYI I don’t own a F150 but really wanted one to tow with one when truck shopping. I really like the styling but the one thing that held me back was I couldn’t figure out what the hell Ford was doing with the ratings. It was this forum and another that shyed me away from getting the truck besides pricing that is. So I’m in a heavier truck from another manufacturer to pull a 8k TT and I don’t regret it. But the ratings thing has been driving me nuts for almost a year now.

 

No one is arguing that you can use apply the GAWR or GVWR to increase the tow rating. We are simply saying that you can use the additional AWR and GVWR to achieve Ford's advertised tow rating (or at least get much closer to it than a regular F150

Please quote the rating you think you would be "increasing"...

This is actually a very good question. @johndeerefarmer, IIRC, you either 5th wheel or GN pull...what are your weights?