Question regarding 5th wheel pin weight

[Herk7769]

Originally Posted by CWSWine

It was explained to me that the difference in total axle weights and the GVWR is because the Axle Ratings are based off static weight. During towing static weight can increase by 30% or more - like you are going down a hill and put the brakes on the weight from the RV will shift forward on to the pin. The guy that was explaining this was a worked for Ford in the engineering department and now retired and teaching at college engineering classes part time.

Thank you, I have no doubt you are correct.

In my case (2008 GMC Sierra 2500HD Crew Cab), the GVWR is 9300 pounds; in 2010 the company made a frame change from "C" to "Boxed" and the GVWR increased to 10,300 pounds with identical axles front and rear.

[CaptnJohn]

3

Originally Posted by checkmate99

Pretty sure Forest River's published dry weights include full propane tanks.

All builders weigh with full propane since 2013

[CWSWine]

Originally Posted by Herk7769

Thank you, I have no doubt you are correct.

In my case (2008 GMC Sierra 2500HD Crew Cab), the GVWR is 9300 pounds; in 2010 the company made a frame change from "C" to "Boxed" and the GVWR increased to 10,300 pounds with identical axles front and rear.

That does sound like the frame is the limited factor and not the axles.

[MillerTime]

Originally Posted by Herk7769

Thank you, I have no doubt you are correct.

In my case (2008 GMC Sierra 2500HD Crew Cab), the GVWR is 9300 pounds; in 2010 the company made a frame change from "C" to "Boxed" and the GVWR increased to 10,300 pounds with identical axles front and rear.

Front axle and suspension components changed as well as internal parts in the rear housing from what ive read. Brakes are bigger too if i recall correctly. As well as hub/lug size.
This is what i had seen from the comparisons of the 2010 to the updated 2011 chassis. The new chassis is also reportedly about 300lb heavier than the previous one.

Heres my sticker ratings for my gmc 3500. Axle ratings about 1950 lb more than gvwr.
I dont know why some people will throw out the gvwr and only go by the individual axle ratings.

[Herk7769]

Originally Posted by MillerTime

Front axle and suspension components changed as well as internal parts in the rear housing from what ive read. Brakes are bigger too if i recall correctly. As well as hub/lug size.
This is what i had seen from the comparisons of the 2010 to the updated 2011 chassis. The new chassis is also reportedly about 300lb heavier than the previous one.

Heres my sticker ratings for my gmc 3500. Axle ratings about 1950 lb more than gvwr.
I dont know why some people will throw out the gvwr and only go by the individual axle ratings.

Thanks. I was repeating what I was told by the dealership when I asked about the changes. Not a motorhead myself. I do know just enough not to overload my truck.

[MillerTime]

Originally Posted by Herk7769

Thanks. I was repeating what I was told by the dealership when I asked about the changes. Not a motorhead myself. I do know just enough not to overload my truck.

Thats just what id read.
I know the wheels wont interchange though.
I do know my new truck has a lot more beefy looking parts than my old duramax.

Anyways....carry on!

[fljl]

Originally Posted by RubberNail

You'll find conflicting opinions on this. I've been RVing since the mid 70s, pulled and driven most all of the different types, from slide-in campers to class "A's". Currently have a class "C" MH and a 33' 5th wheel. I got out of two 1 ton DRW to get a 3/4 SRW so I could park where I wanted, and go thru the car wash. My rule is don't exceed the GCWR of the truck (truck + trailer) and don't exceed the rear axle rating, in my case 6000#. I don't worry the GVWR unless what I'm pulling, or hauling, is something that doesn't have it's own brakes (read slide-in camper). Too many people trading away perfectly capable trucks to achieve a payload capacity that's not necessary. Two parameters with trailers: GCWR and RAWR!!

I agree totally, all highway trucks are rated by each axle added together, moving or standing still. It's the small trucks that have a payload # that does NOT add up to axles.

"In reality if you add the front and rear axle ratings together, you will find the total is more than the Gross Vehicle Weight Rating of the truck. The reason for this is the frame of the truck is the limiting factor in every case (I have found anyway). Yes, it is possible to be under your individual axle ratings, yet still be overloaded."

However are there any HEAVIER parts other than springs between the 2500 HD and SRW 3500HD GMC's? When I do the math I get a diff of 30lbs in truck weight. I say NO, till check parts at dealership.

Maybe the people who bought TOO big a truck only go by GVWR?

[CaptnJohn]

Originally Posted by fljl

However are there any HEAVIER parts other than springs between the 2500 HD and SRW 3500HD GMC's? When I do the math I get a diff of 30lbs in truck weight. I say NO, till check parts at dealership.

Maybe the people who bought TOO big a truck only go by GVWR?

I have had several Ford people tell me the only difference is in the springs and the F250/F350 badge on the hood. Frame, brakes, drive train all the same. Difference can come with options which can change axel ratings.

I used to think there could not be too much truck. Then I bought a 1 ton dually. Huge mistake. My F250 diesel with a 2472 payload and 15,100 trailer comfortably pulls my 5er. Hard enough at times finding a parking place big enough even when pushing the button to withdraw the mirrors. They don't make parking spaces for anything but a Honda any more.

[fljl]

The Initial costs between 2500 and 3500 are NOT much diff, how much could springs cost? Will let you know.

[Herk7769]

I do know this; GVWR is based on the part that will break FIRST. It says absolutely nothing about which part will break second.

I had this talk with an engineer at Lippert when I wanted to upgrade my axles and brakes to increase the payload of my Ultralite.

They said that doing so would not help with my payload and be a waste of money. He said that to order to find the actual weight increase (if any) by replacing a potentially "controlling part" and actually finding out what the next "controlling part"'s weight restriction was, they would have to go back and re-engineer the camper with that part installed.

The stiffer axles would cause different forces to be exerted on the totality of the design than when the initial design study was done.

There would be no way to tell what would break next without a new study. It could be the frame from the stiffer ride; it could be the side walls from not having enough stiffeners (interior framework) to support the increased weight (resulting in cracks at the window and slide penetrations); or it could be the pin box mounting structure.

Trucks, cars, RVs, and aircraft all use similar modalities of failure modeling.

You exceed plated numbers at your own risk.

[CWSWine]

With all the "Best In Class Payload" ads going on between Ford, Chevy and Ram it's funny that Ford and Chevy sticks to the 11,500 GVWR and Ram jumped theirs up to 12,300 GVWR on their SRW 1 ton. Maybe there is a limited factors on the Ford and Chevy that doesn't allow for the higher GVWR ratings and exceeding the 11,500 exceeds those limits. I'm sure the advertising arms of Chevy and Ford would love to have the higher GVWR and the higher payloads.

[ependydad]

Originally Posted by Herk7769

The reason for this is the frame of the truck is the limiting factor in every case (I have found anyway).

I wonder about this as it's often postulated that "the only difference between a 3/4-ton and 1-ton are the XYZ". I can't imagine the frames really are different between the two - or even between the SRW and DRW.

BUT- I'm far from a motorhead. "Righty tighty, lefty loosey" is my level of mechanical ability.

[CaptnJohn]

Originally Posted by ependydad

I wonder about this as it's often postulated that "the only difference between a 3/4-ton and 1-ton are the XYZ". I can't imagine the frames really are different between the two - or even between the SRW and DRW.

BUT- I'm far from a motorhead. "Righty tighty, lefty loosey" is my level of mechanical ability.

MO the cost of different frames on a single assembly line would be a limiting factor. Waiting to see how the aluminum body on Ford Super Duty works on payload as they suggest a 700# weight savings.

[CWSWine]

Originally Posted by CaptnJohn

MO the cost of different frames on a single assembly line would be a limiting factor. Waiting to see how the aluminum body on Ford Super Duty works on payload as they suggest a 700# weight savings.

I don't think have different frames would be a cost issue since they have different engines, transmissions, tires, dashes, radios, body colors, rear ends, seats, length of frames, bed size and etc already on the same line. Just one more thing.

I would like to know the payload ratings and etc on the new 2017's.

[MillerTime]

Originally Posted by ependydad

I wonder about this as it's often postulated that "the only difference between a 3/4-ton and 1-ton are the XYZ". I can't imagine the frames really are different between the two - or even between the SRW and DRW.

BUT- I'm far from a motorhead. "Righty tighty, lefty loosey" is my level of mechanical ability.

Some time when im caught up at work i can look up frame specs for any model. I dont know how many options there are for certain years and model. I do know that a few weeks ago we were measuring a 1500 dodge frame and there were at least 2 if not 3 different frame specs available. Wasted a lot of time having to input each one and then measuring just to find out it was the wrong spec.
-I'd just need a certain year, make and model and 4 or 2wd and wheel base measurement is helpful, to get specs

[Herk7769]

Originally Posted by MillerTime

Some time when im caught up at work i can look up frame specs for any model. I dont know how many options there are for certain years and model. I do know that a few weeks ago we were measuring a 1500 dodge frame and there were at least 2 if not 3 different frame specs available. Wasted a lot of time having to input each one and then measuring just to find out it was the wrong spec.
-I'd just need a certain year, make and model and 4 or 2wd and wheel base measurement is helpful, to get specs

I certainly would appreciate a comparison of the 2008 GMC Sierra 2500HD Crew Cab 2WD and the 2008 GMC Sierra 3500HD Crew Cab 2WD.

It would make me a believer in upgrading axles etc. My money is on "there is a difference", but would LOVE to be proven wrong.

[menekaunee]

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