Tow Vehicle GARS vs GVWR

LarryJM wrote:

transamz9 wrote:

LarryJM wrote:
The real answer which no one has mentioned IMO is that the vehicle must pass stringent braking standards such as fade, temps, etc. based on a specific number which is the GVWR and it would be cost prohibitive to have all the various GVWRs certified so you will generally find one class of vehicle with a specified GVWR and then for different axle and tire options and even some suspension options you will get various axle wt. ratings whose sum often don't equal the GVWR for that vehicle. A good example is my Van where with the diesel engine there is an option for what is called "ONE UP FAWR" which increases the FAWR 200lbs, but has zero change to the vehicles GVWR.

Larry

That's weird because a lot of 250/2500's have the exact same brakes as the 350/3500.:h

Doesn't matter since both undergo separate independent brake testing so each have a separate certification for that class vehicle. If they have the same braking system it just means the lower GVWR preforms better than the higher GVWR, but both meet or exceed the required performance standards. It is totally up to the manufacturer to specify what the GVWR is as long as it is less than or equal to the sum of the two lowest GAWRs for all the potential factory option combinations.

One thing I'm not sure of is how they handle the various tire options within a class of vehicle as far as testing goes.
Larry

Well if they need to test each different GVWR, then Ford needed to test and certify a slew of F150's!!!
Look at the payload tab of this document. For the 4X2 reg cab I counted 5 different GVWR, looks like 6 for the Super cab 4X2.

F150 GVWR

When my 01 was built Dodge didn't change the VIN to reflect that I had 265/75 - 16 RE tires, the Vin still shows 245/75-16 RE. They are part of the Camper package on the 2500, that rear sway bar and 3500 springs.

transamz9 wrote:

LarryJM wrote:
The real answer which no one has mentioned IMO is that the vehicle must pass stringent braking standards such as fade, temps, etc. based on a specific number which is the GVWR and it would be cost prohibitive to have all the various GVWRs certified so you will generally find one class of vehicle with a specified GVWR and then for different axle and tire options and even some suspension options you will get various axle wt. ratings whose sum often don't equal the GVWR for that vehicle. A good example is my Van where with the diesel engine there is an option for what is called "ONE UP FAWR" which increases the FAWR 200lbs, but has zero change to the vehicles GVWR.

Larry

That's weird because a lot of 250/2500's have the exact same brakes as the 350/3500.:h

Doesn't matter since both undergo separate independent brake testing so each have a separate certification for that class vehicle. If they have the same braking system it just means the lower GVWR preforms better than the higher GVWR, but both meet or exceed the required performance standards. It is totally up to the manufacturer to specify what the GVWR is as long as it is less than or equal to the sum of the two lowest GAWRs for all the potential factory option combinations.

One thing I'm not sure of is how they handle the various tire options within a class of vehicle as far as testing goes.
Larry

sidney wrote:

45Ricochet wrote:

Maybe now tell us the positive and negative sides of Viagra :E Must be winter :W

Ah...it's interesting you should ask.

Amazingly enough Viagra was discovered by accident... you guessed it... by a 5th wheel owner who was having difficulty with his auto level system maintaining the correct height to allow him to get hitched.

It is also rumored... the very same 5th wheel owner is responsible for developing the "pull test".

Hilarious! :B

Ah...it's interesting you should ask.

Amazingly enough Viagra was discovered by accident... you guessed it... by a 5th wheel owner who was having difficulty with his auto level system maintaining the correct height to allow him to get hitched.

:)

45Ricochet wrote:

Maybe now tell us the positive and negative sides of Viagra :E Must be winter :W

Ah...it's interesting you should ask.

Amazingly enough Viagra was discovered by accident... you guessed it... by a 5th wheel owner who was having difficulty with his auto level system maintaining the correct height to allow him to get hitched.

It is also rumored... the very same 5th wheel owner is responsible for developing the "pull test".

sidney wrote:
The GVWR is determined by using a sophisticated social media / internet forum protocol formula.

(FAWR + RAWR)* X = GVWR

Where X is the "Variable Internet Forum Coefficient" or VIFC.

The VIFC is randomly determined by former NASA technician who were responsible for black tank flush maintenance and winterizing the space shuttles. The former technicians live in Houston TX and enjoy RVing, Camping, Boondocking and LT vs ST tire debates.

The VIFC was developed for entertainment purposes only... to encourage lively intellectual debate among RV enthusiast.

However, the VIFC has sinced morphed into a "COW" (can of worms) that can be taken literally, casually or ignored completely solely dependent upon what size TV you can afford to own. :W

LOL
Maybe now tell us the positive and negative sides of Viagra :E Must be winter :W

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 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.

My point here is brakes are a function of the GAWRs not GVWR. Same with our trailers.

Vehicle manufacturers may determine the GVWR of a vehicle by calculating the maximum load rating of the vehicles axles, tires, brakes, frame, suspension and wheels in order to come up with a GVWR rating. Also, a manufacturer may limit the GVWR if so desired. So they could have the componentry to rate higher but choose a lower rating at their discretion.

The F250/F350 SRW is a good example.
The F250 is rated at 10000 GVWR with 6100 RAWR.
The F350 SRW is the same truck specs and starts at 10000 GVWR but rates the same axle (higher rated wheels/tires and the rear spring pack) with a 6290 RAWR for more payload.
The higher rated 6730 RAWR and 7000 RAWR have the higher rated GVWRs up to 11500 for even more payload.

LarryJM wrote:
The real answer which no one has mentioned IMO is that the vehicle must pass stringent braking standards such as fade, temps, etc. based on a specific number which is the GVWR and it would be cost prohibitive to have all the various GVWRs certified so you will generally find one class of vehicle with a specified GVWR and then for different axle and tire options and even some suspension options you will get various axle wt. ratings whose sum often don't equal the GVWR for that vehicle. A good example is my Van where with the diesel engine there is an option for what is called "ONE UP FAWR" which increases the FAWR 200lbs, but has zero change to the vehicles GVWR.

Larry

That's weird because a lot of 250/2500's have the exact same brakes as the 350/3500.:h

The GVWR is determined by using a sophisticated social media / internet forum protocol formula.

(FAWR + RAWR)* X = GVWR

Where X is the "Variable Internet Forum Coefficient" or VIFC.

The VIFC is randomly determined by former NASA technician who were responsible for black tank flush maintenance and winterizing the space shuttles. The former technicians live in Houston TX and enjoy RVing, Camping, Boondocking and LT vs ST tire debates.

The VIFC was developed for entertainment purposes only... to encourage lively intellectual debate among RV enthusiast.

However, the VIFC has sinced morphed into a "COW" (can of worms) that can be taken literally, casually or ignored completely solely dependent upon what size TV you can afford to own. :W

The real answer which no one has mentioned IMO is that the vehicle must pass stringent braking standards such as fade, temps, etc. based on a specific number which is the GVWR and it would be cost prohibitive to have all the various GVWRs certified so you will generally find one class of vehicle with a specified GVWR and then for different axle and tire options and even some suspension options you will get various axle wt. ratings whose sum often don't equal the GVWR for that vehicle. A good example is my Van where with the diesel engine there is an option for what is called "ONE UP FAWR" which increases the FAWR 200lbs, but has zero change to the vehicles GVWR.

Larry