1st time using Cat Scales, need help analyzing results

RCMAN46 wrote:
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I can not say for the Ford or anything after 2011. But prior to 2011 both Dodge and the GM trucks had the same axle and brakes on both the 2500 HD and 3500 trucks. I believe Dodge and GM even used the same rear axle but may be wrong on that.

i guess i don't see the huge price differences between similarly packaged 3/4 ton and 1 ton trucks... maybe the 3/4 ton of now are really just 1 tons with a softer ride. we had a f350 that would rattle the fillings out of your mouth... i guess if you can just change springs to hit a different market with essentially the same truck that's good business.

Anyone who thinks that the gross weight a vehicle is designed for does not include all components, should have seen what happened when my buddy stuck a dually rear axle assembly under the back of his F-150. He started experiencing failures including transmission damage and frame breakage. He had plenty of axle rating. The manufacturers would love to build one platform and simply vary the rear axle assemblies to suit the buyer's needs.

uzikaduzi wrote:
i'm no expert but generally don't 3/4 ton and 1 ton trucks have different axles... like a f250 used to come with a Dana 50 and the f350 had a Dana 60?...

as far as the actual question i agree with the consensus that you are close and just to be cautious. we had farm trucks that we towed things that far exceed the GVWR although fairly, that was at very low speeds.

I can not say for the Ford or anything after 2011. But prior to 2011 both Dodge and the GM trucks had the same axle and brakes on both the 2500 HD and 3500 trucks. I believe Dodge and GM even used the same rear axle but may be wrong on that.

i'm no expert but generally don't 3/4 ton and 1 ton trucks have different axles... like a f250 used to come with a Dana 50 and the f350 had a Dana 60?...

as far as the actual question i agree with the consensus that you are close and just to be cautious. we had farm trucks that we towed things that far exceed the GVWR although fairly, that was at very low speeds.

Sorry. I thought the OP was talking about gvwr rating for tow vehicle, not trailer. These things sure take off in odd directions.

Back to the original question....both tongue weights are important...you need the 1420 calculated without WD to show you what % of total weight of the trailer is on the tongue, and the 1080 with WD shows you how much weight the trailer adds to the truck going down the road.

I wouldn't worry about being slightly over GVWR if you are under GAWRs and most importantly tire ratings. Be conscious about adding more weight though...

Regarding GVWR, it's not all about capacity. Every OEM design is a compromise of capacity, efficiency and durability. The axles are rated to carry those loads, but the mfr is recommending that total vehicle weight be limited to less for other reasons, likely durability, ride comfort, etc. If you load past GVWR you will likely need accelerated service intervals and may experience faster component wear.

If the mfr allowed a higher GVWR and then recommended a more aggressive maintenance schedule to compensate, you would think the cost of ownership is too high. If the mfr recommended a higher GVWR and didn't increase the maintenance schedule, you may experience frequent repairs and perceive the dependability of the vehicle to be too low.
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Jimlin is correct on axle weights, the GVWR is recommended by the mfr for reasons they don't disclose...the important thing is to be aware of your weights and plan accordingly.

TomG2 wrote:
I can find no mention of stopping as the only criteria in any GVWR definitions that I can find. I still say it "should" be the maximum weight a vehicle is safe and comfortable with. I feel that my 9,200 pound GVWR rated pickup is good up to 9,200 pounds, both going, stopping, and steering. After that????? If GM caught me with a burned out transmission and broken frame while loaded to a GVWR of 12,000 pounds, I don't think they would tell me I was simply overloading the brakes. Point is, they rate the whole truck, not individual parts with the GVWR.

NHTSA says this about brakes;

"Gross Axle Weight Rating is the rated load-carrying capacity of an individual axle and wheel assembly. (It represents the load that may be steadily sustained by the components in the system; i.e., tires, rims, hubs, bearing, axles, brakes, suspension, sub frame, etc. with the GAWR limited by the components with the lowest working rating".

And from AL/KO axles

Weigh the trailer after it is fully loaded and ready for use.
Axles, brakes, wheels, tires, frames and suspension components are
designed to carry a specific maximum weight. Locate the VIN
(Vehicle Identification Number) plate on the trailer. It will show the
GVWR (Gross Vehicle Weight Rating). The GVWR is the total
amount your trailer (including tongue weight) can weigh when it is
completely loaded including holding tanks, propane etc. The GAWR
(Gross Axle Weight Rating) is the maximum load that the axles will
carry and the maximum load the brakes will stop.

And RMA

• GAWR: Gross Axle Weight Rating (for each axle) -
The maximum weight rating that the components
(tires, rims/wheels, brakes, springs, and axle) of
each axle are designed to support. This is
determined by the lowest design capacity of any
component. In other words, if the wheels have the
lowest design capacity of any component on that
axle, installing tires with a higher load capacity
does not increase the GAWR. By regulation, the
tire load rating times the number of tires on that
axle must equal or exceed the GAWR for that axle.

OP wrote:
What I don't understand is, why isn't vehicle GVWR the sum of adding the 2 axle ratings?

Some state size and weight regulations may read the sum of the FAWR/RAWR is it a trucks GVW(R).

The vehicle manufacturer sets GCWR/GVWR/FAWR/RAWR. No one knows how its determined and it can change from year to year.

GCWR number can be changed by a simple gear change/tranny change/ETC and isn't id'd on the truck anywhere nor is it required to be.

GVWR is required to be on the trucks certification placard but isn't used legally to determine how much load the trucks axle/tires may carry.

The GAWRs are also required to be on the truck certification placard and is used to determine how much load a trucks axle/tires may carry. The GAWRs also determine the size of the brake system the mfg has installed on the vehicle.

Good point on 2500 vs 3500 SRW differences being tires/wheels and heavier rated rear springs.

If you look at the GVWR of Ford's 2013 F150s, they range from 6450# to 8200#. The 126" wheel base, 3.7L V6 4x2 is 6450#. With >145" wheel base and the 5L V8 or Ecoboost with HD Payload option, you can get up to 8200#.

Looking at a single wheelbase/engine (157" 4x4 Ecoboost): the GVWR ranges from a base 7350#, to 7700# with the MaxTow option, to 8200# with the HD Payload option. AFAIK the MaxTow adds additional engine and tranny cooling (+ other options for trailer towing). HD Payload adds a 7 lug wheels/axle (+increased rear GAWR), heavy duty suspension and LT metric tries.

AFAIK all these trucks have the same braking system.

I can find no mention of stopping as the only criteria in any GVWR definitions that I can find. I still say it "should" be the maximum weight a vehicle is safe and comfortable with. I feel that my 9,200 pound GVWR rated pickup is good up to 9,200 pounds, both going, stopping, and steering. After that????? If GM caught me with a burned out transmission and broken frame while loaded to a GVWR of 12,000 pounds, I don't think they would tell me I was simply overloading the brakes. Point is, they rate the whole truck, not individual parts with the GVWR.