can someone please explain this for me?

your short box also negatively impacts your towing capacity as well I think?

SUMRX4 wrote:
...Also why would you calculate the weight of the axle itself into the payload? The axle weight is resting on the ground not the suspension. That one doesn't make sense to me.

They need to justify exceeding their ratings somehow; don't be interjecting common sense.
Your answer is, a conventional trailer has 10% - 15% tongue weight. A fifth wheel has 20% - 25% pin weight. Either way, tongue weight or pin weight goes against your payload rating. That is why you can pull a lot more conventional trailer then fifth wheel and still remain within your ratings.

JIMNLIN wrote:

According to this my max trailer weight without a 5th wheel is 12,500 and with a 5th wheel it drops to 10,600. Why is that?

No one knows why a truck makers assigns ratings to a particular truck. Its been this was since mfg started assigning numbers to their trucks. RV folks like to guess and some guesses get pretty wild.

However we do know a 5th wheel trailer places all the hitch weight (pin weight)..plus the weight of the hitch itself over the trucks rear axle. That model F250 has either a 6084 or 6100 RAWR. These year model F250 rear axle can weigh in the 2900-3000 lb range leaving around 3000-3200 lb for a in the bed payload.
You have the truck so drop by a set of CAT scale and get your trucks front and rear axle weights. These are the numbers that will tell you what the truck can safely handle in all situations.
The RAWR includes rear axle assy....tires....wheels...brakes....rear spring pack.
Now if your F250 has the heavy service package or camper package the front and rear brakes...suspension is upgraded two times. Same as a F350srw GAWR packages.

Apparently you know your Fords pretty good. My rear axle is rated at 6084. How would I go about finding out if this truck was equipped with the camper package or anything like that?
Also why would you calculate the weight of the axle itself into the payload? The axle weight is resting on the ground not the suspension. That one doesn't make sense to me.

The 12,500 is likely your receiver hitch rating limit. A TT will have about 13 percent hitch wt added to payload of truck, while a FW pin wt will be 20-25 percent. However the FW wt is mostly confined to the rear axle, so Jim's description above applies.

Jerry

According to this my max trailer weight without a 5th wheel is 12,500 and with a 5th wheel it drops to 10,600. Why is that?

No one knows why a truck makers assigns ratings to a particular truck. Its been this was since mfg started assigning numbers to their trucks. RV folks like to guess and some guesses get pretty wild.

However we do know a 5th wheel trailer places all the hitch weight (pin weight)..plus the weight of the hitch itself over the trucks rear axle. That model F250 has either a 6084 or 6100 RAWR. These year model F250 rear axle can weigh in the 2900-3000 lb range leaving around 3000-3200 lb for a in the bed payload.
You have the truck so drop by a set of CAT scale and get your trucks front and rear axle weights. These are the numbers that will tell you what the truck can safely handle in all situations.
The RAWR includes rear axle assy....tires....wheels...brakes....rear spring pack.
Now if your F250 has the heavy service package or camper package the front and rear brakes...suspension is upgraded two times. Same as a F350srw GAWR packages.

Many F250's you see pulling 5ver's are way over on pin weight. Most everyone assumes these a big pickem up truck and can carry anything. I know I was very surprised/disappointed to find out my then F250PSD only had about 1800lb cargo capacity and most decent size 5th wheels are much more than that hitch weight.

That is why I traded my 2004 F250 after finding out the 10,600 lb 5th wheel limit. I didn't buy a 5er until 2007. If I remember correctly they boosted that 5th wheel rating in 2005 to a much higher number. But I bought a 2007 F350 to make sure the 5th wheel rating was high enough for me.

Actually, for that vintage, even a 10k FW might be over spec. I know I am with my '02 D'max, but it's not so far that I worry about it. Given that the rear ends of most 3/4t and 1t trucks are almost identical, except for some springs, is another reason I don't worry much, if it's close.

Lyle

With Fifthwheels, it's not so much "How Much You can Pull', but "How Much can You Carry". A 12.5K 5er would have a typical pin of approx 2500 Lbs, which in may cases would exceed you carrying capacity, while that 10.6 would have a typical pin of just over 2K that would most likely be within your specs.