I have a document that I used for some research when I first got my truck. You might find some of the information valuable. I didn't break it down into detailed explanations, but if you have any questions, I'll try to answer.
My Truck is a 2000 F250, XLT, Super cab (extended), Short bed, 2WD with a 6-speed manual, and a tool box. When I scaled it, I pulled out my 5th wheel, took the ball out of the hitch, emptied everything from the bed, cab, and tool box, fueled it until diesel was coming out of the filler neck (not foam), and it came out to a weight of 6,660 lbs without driver. I also took a snapshot of the cat scale print out for you.
My Truck
- Weight IAW specifications pdf:
- Extended cab 4x2 base curb weight: 5237
- Power stroke/6spd = +680
- Tool box (empty): +150
- 5th Wheel: +250
- Options
o A/C +44
o XL +6
o Hitch Receiver +49
o Power doors/locks +15
o Running boards +64
- = 6495 lbs calculated curb weight
- 6660 lbs actual scaled curb weight
- 6900lbs scaled “race weight” with me and nothing else (including 5th wheel and full tank of diesel)
- BLUF = limiting factor is 1) receiver/hitch, which is limited to 10,000 lbs. 2) w/ Upgraded hitch, truck is limited at 13,100 lbs, and at the 1,900 lbs hitch weight limit, hitch weight would be at 14.5%.
- 20,000 lbs GCWR
o Towing capacity
 5th wheel = 20,000-6900= 13,100 lbs
• Tongue weight for 5th wheel should be 17-25% = 2262-3326
 Bumper pull = 10,000 lbs (hitch capacity, perhaps?)
• 10-15% tongue weight = 1,000-1,500 lbs
- 8,800 lbs GVWR (max on all 4 tires)
- GAWR (Gross axle weight rating)
o Front = 4250 lbs
o Rear = 6084 lbs
 Weight bias = 60/40
• Front (race weight) = 3920 lbs (580lbs remaining)
• Rear (race weight) = 2980 lbs (3104 lbs remaining)
o 10% = 31,040
o 15% = 20,693
o 20% = 15,520
o 25% = 12,416 lbs
- Payload = 8,800-6,900 = 1,900 lbs
o Bumper pull
 Max trailer at 10% hitch weight = 19,000 lbs
 Max trailer at 12.5% hitch weight = 15,200 lbs
 Max trailer at 15% hitch weight = 12,667 lbs
o 5th Wheel
 Max trailer at 15% hitch weight = 12,667 lbs
 Max trailer at 17% hitch weight = 11,176 lbs
 Max trailer at 20% hitch weight = 9,500 lbs
 Max trailer at 25% hitch weight = 7,600 lbs
- ZF6 transmission (L-5.79, 1-3.31, 2-2.1, 3-1.31, 4-1.00, 5-.72, R-5.23)
- Rear gear = 3.73
- Tires: 265/75/16
- Wheels: 16x7
Web research:
4x4 vs. 4x2 = ~400 lbs
7.3 engine: 960-1100lbs (best guess 1000, but not includes turbo stuff?)
6.8L V10: 650
5.4: best guess 500lbs
Regular cab vs. supercab: 166lbs
SC vs. Crew Cab: 354 lbs
RC vs. CC: 416
ZF6 6-spd manual: 235 lbs (300 with clutch, fluid, & bellhousing?) – specifications pdf makes it out as heavier than the Auto
4R100 Auto: 250 w/o convertor, 300 w/ convertor, 350 w/ fluid
Short bed vs. long bed:
- Supercab = 218lbs - 231
- Crew cab = 136-169
It appears that the limitation on rear GAWR is the Tires, followed closely by the springs. From online research:
Found this article on fourwheeler.com that might shed some light:
Ford 10.25 & 10.50-Inch Axle Tips - Axle Examination
Found under: '99-'05 F-250 and F-350
Type: Full-float
Weight (lb., approx): 333 (single wheel), 348 (dual wheel)
Ring gear diameter (in.): 10.50
Pinion shaft length (in.): 10.50
Pinion shaft spline count: 31
Axleshaft spline count: 35
Axleshaft diameter (in.): 1.5 (at the splines)
Hypoid offset (in.): 1.50
Gear ratio range: 3.08-7.17
Brakes: Disc
Normal GAW range (lb.): 9,750 (single/dual wheel)
Nominal GCW rating (lb.): 26,000 (single/dual wheel)
Output torque maximum (lb-ft): 10,660 (single/dual wheel)
Output torque continuous (lb-ft): 2,900
Ford 10.25 & 10.50-Inch Axle Tips - Sterling 1050 - Four Wheeler Magazine
