Truck GVWR

[atom ant]

I thought I knew GVWR pretty well, but trucks are throwing me off. A trailer GVWR is based on the limiting factor of axle rating (or tire) and design pin weight.

However what is the limiting factor that truck GVWR is based on? If an F350 SRW quad cab has a 7,000 lb Rear axle capacity and 6,000 lb Front axle capacity and tires rated at 3,650 lbs each, why is the GVWR on only 11,500 lbs rather than the full 13,000 lbs of the axle capacity?

My daughter daughter bought a LANCE truck camper that is just cool as it can be but we are trying to figure out her capacity.

[Ford truck guy]

Brad,

Ive always wondered that myself...

My tires combined are rated for 3750#, or a total of 7500# and my axle capacities have always been close, but under..the 7100# listed

Those are the 2 limiting factors in my eyes... weakest links...

[Shane Wood]

Originally Posted by atom ant

I thought I knew GVWR pretty well, but trucks are throwing me off. A trailer GVWR is based on the limiting factor of axle rating (or tire) and design pin weight.

However what is the limiting factor that truck GVWR is based on? If an F350 SRW quad cab has a 7,000 lb Rear axle capacity and 6,000 lb Front axle capacity and tires rated at 3,650 lbs each, why is the GVWR on only 11,500 lbs rather than the full 13,000 lbs of the axle capacity?

My daughter daughter bought a LANCE truck camper that is just cool as it can be but we are trying to figure out her capacity.

Brad I just checked my truck and axle weight adds up to 15000 lbs and GVWR is 13025 lbs

[atom ant]

That's strange they stay short of the axles and tires. I told her at the very least make sure not to overload the rear tires, or even the axles, but I think she is already over GVWR.

[mhs4771]

Brad, no rhyme or reason on some of their numbers. If you think she is OK with the setup, I would run it across some scales to see exactly what the setup weighs and if over the GVWR I would see if the Truck can be licensed for a higher gross. I knew with our Pin weight, hitch, tool box and everything else we carry that I was close to our GVWR so I have my Truck licensed for a gross of 14,999 Lbs, was going for 15K, but that was the next price bracket. So I'm licensed for the weight I'm carrying.

[piper guy]

Brad, I think you're limiting factor will be the rear axle and tires with the camper. With the camper on it will probably unload some of the weight off the front axle.
I've wondered the same thing as far as GVWR and the conclusion I came to is that this is what the axles are rated for and this is the max we want the truck to weigh - you figure it out how you want to load it. For instance if that same truck had a commercial snowplow mounted on the front, you'd very quickly be close to the 6k front axle rating.

Kind of like loading a small plane for weight and balance. "This is how many pounds you can carry, distribute it the way it works best"

[Garyl53]

I have never been able to make sense of the GVWR ratings. I had an F250 rated at 10000 GVWR. The tire label indicated 65 psi front and 65 psi rear. An F350 had identical parts: axles, springs, wheels, tires, rear overload springs, etc. but was rated at 11500 GVWR. The only difference I could see was the tire label called for 65 psi front and 80 psi rear. I think it is more important to make sure you aren’t overloading the weakest component wether that is the wheels, tires or axles, etc. Of course an overloaded vehicle doesn’t ride very well so that might determine the practical limit!

[xtasee]

One thing that confuses a lot of people is the rear axle ratio. With all other equipment being the same (including bed length), 6.0 liter GM shows towing capacity at 16,600 for 3.73 ratio and 21,100 on the same truck with 4.10. I can only assume ring and pinion gear/transmission heat would be the limiter....

[atom ant]

Thanks all,
She is at 11,700 without food and water, with a GVWR of 11,500. I showed her your comments and told her to load it and CAT scale it again, with the 7,000 lb axle weight being the red alarm, and the tire capacity of 7,400 or so being the absolute no-go.

Gotta love that phone in CAT scale app where you don't have to reach up to that button!

[piper guy]

I hate to say it Brad but a dually may be in her immediate future if its a really big Lance. I looked at their big one and the first words out of the Salesman's mouth (believe it or not ) was "don't even think about this one unless you've got a Dually".



Amazed me, a sales person that actually wan't lying !! Spent the next hour talking to him and may seriously consider one now that we're stationary here for a while.

[atom ant]

Originally Posted by piper guy

I hate to say it Brad but a dually may be in her immediate future if its a really big Lance. I looked at their big one and the first words out of the Salesman's mouth (believe it or not ) was "don't even think about this one unless you've got a Dually".



Amazed me, a sales person that actually wan't lying !! Spent the next hour talking to him and may seriously consider one now that we're stationary here for a while.

It's just the 850. No slide and pretty common model for a long bed, but it does have a Gen and AC. Wet spec is 2,850 but we know how those go Dry is 2,500 lbs. Her F350 cc is 3,770 lbs, so its tight.

She wouldn't be the first Smeaton to show up to the party with not enough truck the first time

It's a nice looking rig though - been in a barn next to a pristine 2001 Toy Hauler that is also for sale. What happened to those days when you could buy a camper for $6,000 and be happy as can be?

[Shane Wood]

Originally Posted by atom ant

It's just the 850. No slide and pretty common model for a long bed, but it does have a Gen and AC. Wet spec is 2,850 but we know how those go Dry is 2,500 lbs. Her F350 cc is 3,770 lbs, so its tight.

She wouldn't be the first Smeaton to show up to the party with not enough truck the first time

It's a nice looking rig though - been in a barn next to a pristine 2001 Toy Hauler that is also for sale. What happened to those days when you could buy a camper for $6,000 and be happy as can be?

Nice looking rig Brad congrats to her

[atom ant]

Thanks Shane, I'll tell her!

[markw]

For what worth. I still have my 20 year old Lance 920. For 9 years I carried it on a 2500 Chevrolet Silverado, with a 6.0 and speed auto. The first time out I stopped at a cat scale. Fully loaded for 2 weeks. 😱😱 9710 #s. On an 8600 gvwr.

The good part was being about 300 #s under the tire rating on both ends. Drove it for 9 years. Including all the way to Fairbanks. I never had a tire problem in 80k miles. My truck was before GM went to the more Ford like HDs.
Mark

[atom ant]

Originally Posted by markw

For what worth. I still have my 20 year old Lance 920. For 9 years I carried it on a 2500 Chevrolet Silverado, with a 6.0 and speed auto. The first time out I stopped at a cat scale. Fully loaded for 2 weeks. 😱😱 9710 #s. On an 8600 gvwr.

The good part was being about 300 #s under the tire rating on both ends. Drove it for 9 years. Including all the way to Fairbanks. I never had a tire problem in 80k miles. My truck was before GM went to the more Ford like HDs.
Mark

Thats comforting to know Mark and thanks for the input! I think the tire is going to be the limit. She does not have airbags and I notice her truck doesn't even sag in the back.

She corrected me - its a Model 1010 - they didn't have a 850 in 2001, so hers is 18 years old already, but having it stored inside really kept it in good shape.

[BobJudy71]

There’s a common misconception that a truck’s GVWR is determined by adding gross axle weight ratings (GAWRs) together for all axles. Although this was a common way of calculating GVWR many years ago, it’s no longer an accurate method. The chassis manufacturer task of establishing a vehicle GVWR is much more difficult today due to advancement of safety system standards and how vehicles meet these requirements. This is why many trucks have a GVWR much lower than the combined axle ratings. It is not uncommon for a truck with a GVWR of 19,500 pounds to have a front axle rated at 7,500 pounds and a rear axle rated at 14,700 pounds. Safety standards that apply to braking, vehicle stability, and chassis manufacturer internal standards for durability, dynamic stability and handling can restrict GVWR even though the sum of the axle ratings exceeds 22,000 pounds. In this instance, the OEM set the GVWR at 19,500 pounds based on test results and vehicle dynamic performance to ensure a safe, reliable truck.

A specific vehicle’s GCWR is based on parameters established by chassis manufacturers. The manufacturer makes an assessment in accordance with SAE International test protocols, determining maximum GCWR. Additionally, the OEM runs stringent tests based on internal requirements which may include testing total GCWR braking capability using only the towing vehicle chassis braking system. GCWR is the total weight of the truck pulling the trailer and the trailer itself. The truck chassis dictates proper GCWR for safe operation of the combination truck and trailer.

From NTEA.com

[atom ant]

Thanks BobJudy71! Although I didn't verify the reference because that site is a "cookie monster", I understand a little better now that it's more complicated than just a single limiting factor. It seems that by meeting international standards, they have other limiting factors.

Interesting - reading the article it seems the truck manufacturers really have to balance the market approach. To stay in front on trailer towing capacity, you might have to sacrifice payload capacity to meet the braking standard in other countries, and both are big sell numbers for trucks.