Do I have this math/ understanding right?

gattorgetter wrote:
Got a new 2020 GMC 2500 with DMax.

Door sticker says just over 3300 for payload. Tires are 3750.

So... manufacture's say hitch weight for xx toyhauler is.... let's say 3500lbs... im guessing that is empty... now if I load 2000lb in garage... the 3500lbs hitch weight could/should be less?

Well the listed Payload is 3,300# and tires are rated at 3,750# ea.

How about the GVWR, and the rear axle rating.

That and scaled weights of the Truck with a hitch and your family.

I ask the GVWR, as GM seems to be playing games with the GVWR of their 2500's and going beyond the 10,000# max for Class2.

Once a TH is loaded for travel with toys and food, cook ware, stuff, and clothing. the pin will likely a bit more than the dry weight depending on how much stuff you carry.

So even going by tires at 3,750# you could put 7,500# on that axles if ready to tow it scales 3,500# that is only 4,000# for a dry pin of 3,500# you are very close.

I guess my big question is WHY NOT buy at least a 3500 SRW to tow a larger TH.

If I did the math right, the 3500 pounds on my trailer hitch is reduced by 330 pounds if I put my 1000 pound Harley in the garage. If I put in my 1300 pound RZR the weight is reduced by 440 pounds.

Of course this was just a basic calculation that didn't figure in adding food and personal items, and other stuff.

Still, I wouldn't carry a huge toy hauler on a 2500 truck.

You figger this out using lever math with the center of the trailer axle group as the fulcrum for cargo behind the trailer axles. The distance from the king pin to the cargo center of gravity is the length of the lever.
Use beam or bridge math for cargo between the king pin and the trailer axles. The cargo weight is distributed to the king pin and axle group center in proportion to its distance from each.

It is possible to calculate weight distribution very accurately this way, even with a pencil and paper.

gattorgetter wrote:
Got a new 2020 GMC 2500 with DMax.

Door sticker says just over 3300 for payload. Tires are 3750.

So... manufacture's say hitch weight for xx toyhauler is.... let's say 3500lbs... im guessing that is empty... now if I load 2000lb in garage... the 3500lbs hitch weight could/should be less?

Are you looking at fifth-wheels (pin weight) or bumper pulls (hitch/tongue weight)?

If your goal is to stay within all the specs, the tires aren't really relevant (assuming they are not lower rated replacements from OEM). The manufacturer already accounted for them with the playload figure.

Yes, loading the garage will reduce the pin weight but probably not as much as you might hope.

As mentioned, if the pin is 21ft ahead of the axles and the CG of the toys is 7ft behind the axles, your 2000lb of toys will only take around 660lb off the pin weight...except anything you load ahead of the axles will add weight back onto the pin. So unless you run empty except the toys, don't expect the pin weight to go down by any appreciable amount.

Another issue...Unless you are a 150lb driver in an otherwise empty truck, you already used some of your payload. Wife, kids, dog, firewood, tool box, hitch, etc..all count against the payload...So you could be looking at a remaining payload of maybe only 2500lb if you have a family of 4 and pack like normal people.

Fully loaded (with toys) you should be looking at 20-25% of the GVW of the trailer on the pin. Only way to tell for sure is to take it down to the scales fully loaded with family aboard and get the real weights.

No toyhauler yet... starting to shop again..

Yep. By the time you add 4 people, firewood, a cooler full of beer, exta gas for the toys....you MIGHT have 2500 pounds of payload left. What's your tongue weight again?

gattorgetter wrote:
Got a new 2020 GMC 2500 with DMax.

Door sticker says just over 3300 for payload. Tires are 3750.

So... manufacture's say hitch weight for xx toyhauler is.... let's say 3500lbs... im guessing that is empty... now if I load 2000lb in garage... the 3500lbs hitch weight could/should be less?

Yes, it will be less, sometimes a lot less. It depends on what you're hauling in the garage. Some people have had their hitch/tongue weight drop too much and resulted in poor handling.

I never noticed much difference with my toy hauler loaded or empty. Remember you have to add anything in the truck to that max payload, people, gear, dogs, firewood, etc.

The rear overhang from the axles is far less than the front overhang. The toys just behind the rear axles will not make up for all the stuff you put forward of the axles. And you will put a lot there. So no, your pin weight will not decrease. It will increase when loaded for travel.