All of the *RATINGS* matter and they make up the whole system.
To take any one is to out of context
Like MTWR (max tow weight rating) that most take as an absolute. Meaning
that the OEM used a 'curb' vehicle with one option (tow option) and
one 150 lb driver to derive/certify the MTWR
Take my Sub as I know that best
The rear GAWR is 6,000 lbs and know the supplier to GM rates it at
10,000 GAWR. The 1 ton dually of that same year has the same axle
assembly, but has different brake cylinders, MC and proportioning valve
That the front GAWR is 4,250 lbs and I ordered it with the F60 option,
which is the snow plow prep...which begets the 1 ton torsion bars
The 1 ton dually has a front GAWR of 5,250 lbs (IIRC) and I have the
same torsion bars via option F60
So could I then say my 8,600 GVWR is bogus and it should be 5,250 + 10,000 ?
To have a 15,250 GVWR? Nope, there are other factors
The OEMs have to provide warranty and still stay in business. So their
certification process for DOT listing also has baked into those *RATINGS*
whatever is necessary for the vehicle to perform to DOT spec and not
break down in the warranty period
Liability is also on the table and why OEMs publish their specifications
and *RATINGS*
Note that all of those spec areas as a *R* in them...GVWR, GAWR, GCWR,
MTWR, etc
So back to why the differing numbers/ratings? We outsider will never
know. Even most insider do not know, but a very few and that is going
to be held very close to their vest because of warranty and liability issues
There are weak links to those food chains....and yes the OEM can change
those ratings without seemingly mechanical changes. That is done
by knowingly accepting the higher MTBF and the higher warranty claims
that comes with a higher MTBF
