jcb206

Just FYI, my 2015 non HDPP weighs 5465. Lbs.

MagneticScrew

Which wheel base? Trim level? Options? Engine?

MagneticScrew

CG is a major factor.

8100hd

Yes it is probably the most important thing to consider.

MagneticScrew

I dont understand the 20" wheels having the higher GCWR. Seems counter productive since the tires are "P" rated soft & weak. Hell, i got rid of my factory "C" rated tires on my HDPP for "E" rated tires. Im still not happy with Ford for putting "C" rated tires on my HDPP. The combined rear tires are rated for 5,070lbs on a 4,800lb axle. A slightly off balance load or heavy road crown and one of the tires will be over max rating.

mass-hole

If a trailer is held constant, does it not take more force to move more mass? So if you have a heavier TV with the same trailer and everything else being the same, why wouldnt it take more effort to move the TV out of line?

And I dont mean how much wind does it take to push a trailer over, thats probably entirely independent of the TV. I'm talking about how much wind it takes to cause the trailer to apply enough force to upset the TV.

If we go by the idea that mass has no effect then should everyone be towing 38' bumper pulls with their 1/2 tons or mid-sized trucks just because it falls within their weight ratings?

My 2014 weighs 6140lbs and has an empty rear axle weigh of 2700 lbs but these new F150's are at 2100-2200 lbs. Thats not a large difference in absolutes but it is in percentage. 23% or so. I dont see how that has zero effect.

8100hd

I don’t think he meant that TV weight didn’t matter but of all factors to consider CG shifts especially rearward will have the most effect on the system.

MagneticScrew

Yes. 8100 is correct. Thats what I meant. CG is part of the equation.

And I do not believe a 6,000lb steel body F150 will have 500lbs more on the rear axle. The AL bodies are only 700lbs lighter for the 157" wheel base. 70% of the weight reduction did not come off the rear axle when a pickup is closer to 60/40 front heavy. Most of the weight savings came off the front axle, as that is why the front springs diameter of the 11-14s were 4" vs the AL body 3.5" diameter springs. And, a 145" crew AL body is not 700lbs lighter. Maybe 600lbs lighter? so.... That math doesn't add up to me but I'm open to hear another theory?

6,000*.42%=2,520lbs
5,300*.42%=2,226lbs

2,520lbs
-2,226lbs
= 294lbs
divided by 2 rear wheels
= 150lbs more weight on each rear tire.

8100hd

In the formulas it’s overall TV mass that counts not just the weight on the rear axle. Just remember that the SAE tow ratings were determined using a cargo trailer with a low CG with torsion axles. Most of us are towing travel trailers with a higher CG and leaf springs which have different dynamics. The SAE sway test requires a certain degree of rotation from the steering wheel during a maneuver during the test. I believe this is the reason Ford changed the steering gear to slow response to pass the test.

MagneticScrew

I will go to the next step for the front axle.

6,000lbs*.58=3,480lbs
5,300lbs*.58=3,074lbs
3,480lbs
- 3,074lbs
= 406lbs
divided by 2 wheels
= 203lbs more on each front wheel for a 11-14 f150 vs 15+
Thats an extra 2 passengers. insignificant.

The weight difference for the average Screw 5.5ft bed is even less.

Steel Screw 5.5ft bed vs AL Screw 5.5ft bed


348 less on front axle divided by 2 wheels = 174lbs difference on each wheel.
252 less on rear axle divided by 2 wheels = 126lbs difference on each wheel.

I can't see how a hundred and something pounds of weight per tire makes any stability difference in any way. The lower CG of the AL body should theoretically make the body feel less side to side movement as well as naturally handle better. lower cars handle better then taller cars, right? Ford kind of lowered the truck without lowering it.