johndeerefarmer

I get tired of reading post after post from the Weight Police for chastising guys for being overloaded. So I compiled a list to show that the HDPP is nothing special.

HDPP truck vs Max Tow truck


The max tow ecoboost F150 has the same 9.75" gearset. Both the HDPP and the “regular” gearset have 34 splines. Only the Raptor gearset is heavier as it has 35 splines. Other than getting a 3.73 instead of a 3.55 the only other difference is that Ford calls for slightly more fluid in the HDPP diff. The axles and axle bearings are identical.

Wheels are no longer 7 lug on the HDPP. Now they all have 6 lug. The HDPP wheels are rated at 2101 lbs vs 1825 lbs for the regular wheel.

If you get the 18” tires you can get the same Goodyear Wrangler AT “c” load range tire that is an option on the HDPP F150

The Supercrew HDPP uses 0.110” thick frame and the other Supercrew 157 uses 0.100” frames so no big increase here.

The max tow trucks have the same transmission cooler as well.

So the real differences between the two are:

Heavier springs.

3.73 gear over 3.55 but the rear is no stronger.

Slightly thicker frame by .01”

Wheels are rated at about 200 lbs more capacity each but the HDPP wheel isn’t even capable of the capacity of the GY Wrangler AT “C” range tire. So if you towed really heavy and often I would upgrade the wheels.


In summary, so how does the HDPP have a 800 or so pound increased capacity when the axles, axle bearings and rear diff are identical? It has to be the springs. Add air bags and you have a HDPP truck except you have a 3.55 rear end and a frame that is .01” thinner

charles_slc

1/100th of an inch doesn't sound like much...

But the other way to look at it is that it's 10% thicker (on all 4 sides) than the standard frame.

I'm an SE not a PE, so I don't know the math off the top of my head...

But if nothing else I suspect Ford wouldn't bother with the extra cost of making different frame thicknesses if it wasn't a real difference.

acadianbob

The connection between these two statements escapes me. But I can only assume:

* You are fine with overloading and, in fact, seem to endorse it
* You are overloaded and don't like hearing about it
* By claiming there is no difference you justify overloading your non-HDPP truck.
* You are looking to provoke an argument

Administrators, I would recommend that this thread be deleted.

Martian

As is, it's a valid discussion.

11screw50

Because the wall is 10% thicker (sounds a lot more significant when you think of it that way instead of 'its only 0.01" thicker' doesn't it?), the HDPP frame has a higher section modulus (6.28 vs 5.73, a 9.6% difference). Since the steel is the same, it has the same yield strength. In simple terms, that means that it takes about 9.6% more force to bend the HDPP to its yield point.

BTW, that also explains why the 2.7 has a lower GVWR. The wall thickness of the standard frame for the 2.7 is only 0.087".

And no, adding air bags will NOT magically make your truck an HDPP equal.

Physics is great, it allows engineers to do their job. The post above (by charles_slc) is correct, there is no way Ford would have any more variations in the frames than necessary, it cuts in to economy of scale and adds cost...but clearly not as much cost as just making all of the frames with the 0.110" wall would add.

McCarthy

So can we do one of these for the 2.7 Payload pack? Curious if it gets the thicker frame etc?

johndeerefarmer

When Ford went aluminum they reduced the GVWR of the max tow truck to 7070 lbs vs the 7700 lbs previously. This just happens to coincide with the 700 lbs that was lost due to the aluminum body. They also reduced the ratings on the wheels and rear axle. Why? Possibly to sell more Super Duty's? After all, if you can get a max tow F150 with way over 2k lbs payload they would sell a lot fewer 3/4 tons.
The frame on the new trucks is stronger than before. Ford states that. The truck is lighter. You can carry what the previous generation did without a doubt.

My payload is over 1700 lbs and I do not have any worries about carrying 500-700 lbs over that. I have done my homework and my truck is equipped for it.

PerryB

Just as an interesting aside (at least to me), my step-brother is a captain for Southwest Airlines and we were talking aircraft weights the other day. When SW buys 737's (that's the only aircraft they fly, to keep a uniform fleet) they can choose the max gross weight (which is the equivalent of GVWR) of the plane between 155,000 lb. and 174,000 lb. The ONLY difference is cost. There are zero airframe or powerplant differences. You just pay extra for the higher weight cert., which is basically an aluminum data plate riveted into the door frame.

smokeywren

If the actual max weight is 174,000, then some buyers might prefer a lower weight rating to save some money on registration or landing fees.


Some airports charge higher landing fees for gross weight over 155,000 pounds. So for shorter routes where the aircraft does not have to be loaded to the gills with fuel, the airline can save on landing fees at those airports by using one certified for less than the true max weight. But if they might use the aircraft for a long-haul flight that requires they top off the fuel tanks, then they need the full 174,000 weight capacity. Southwest has both shorter routes and long-haul routes, so they can use aircraft with both weight limits in their fleet.


However, there are probably differences other than cost. I'll bet the fuel capacity is less in the ones with less weight capacity. That's not a difference in airframe or powerplant specs, but in fuel capacity.


Sorta like the GVWR of the F-350 SRW. The real GVWR is 11,500, but you can order one with a sticker GVWR of 10,000, because some states charge a lot more for registration fees for trucks with GVWR over 10,000 pounds. So you can order the one with GVWR of 10,000 and pay the lesser registration fees, but your truck is identical to the one with GVWR of 11,500 pounds.

marshallr

You answered your own question. Those 3 things can make quite a difference.