New 3/4 CC Dmax payload cap terrible!

On the legality issue, I agree, for the most part. Although, California DMV code does state not to exceed the GVWR of the truck, even if Federal/DOT doesn't say anything about it. Other states are likely similar to California. RV's are not commercial-use vehicles, so most Federal/DOT commercial trucking statutes don't apply to private, non-commercially used RV's.

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I've towed commercially many years before becoming a member of a RV forum. I heard comments like that on occasion so I asked my area state troop captain where to find my states weight codes for RVs. He gave me the deer in the head light stare and said there are no separate vehicle axle or gross weight laws just for a RV or non commercial.
This from a RV.net member asking the state of California if GVWR or GCWR is a enforceable numbers which they aren't. (long-snipped for length and notice it came from commercial enforcement division. Same with my state. Ask DPS about a weight question for a truck pulling a RV and they give out a land line to troop E which is our commercial enforcement guys,.)

This is in response to your electronic mail dated October 14, 2009.
First, allow me to apologize for the untimely response to your e-mail.
My staff recently received your request and by the date of your e-mail,
it appears to have been lost in the system. You were requesting
information pertaining to state laws limiting the gross vehicle weight
rating (GVWR) and/or gross combined weight rating (GCWR) for fifth wheel
and recreational vehicle owners. I have answered each of your questions
in the order asked.

Q: “Many of the owners travel over their tow vehicle GVWR and /or
GCWR. Are there any state laws against this? Or does the owner just
take the risk if they wish?”


A: The California Vehicle Code (CVC) does not contain a law that
specifically limits the amount of weight a vehicle may tow based on the
towing vehicle GVWR or GCWR. There are, however, laws that limit the
amount a vehicle may tow based on other criteria.
Section 1085(d) of Title 13 California Code of Regulations prohibits
the loading of tires above the maximum load rating marked on the tire,
or if unmarked the maximum load rating as specified in the applicable
Federal Motor Vehicle Safety Standard, or in a publication furnished to
the public by the tire manufacturer. This would most likely happen in
the case of a pickup truck towing a large fifth wheel travel trailer, as
those types of trailers tend to transfer a larger portion of their
weight to the last axle of the towing unit causing that axle to exceed
the tire load limits.
I trust this has adequately answered your questions. Should you desire
any further information, please contact Officer Ron Leimer, of my staff,
at (916) 445-1865.
Sincerely,
S. B. DOWLING, Captain
Commander
Commercial Vehicle Section"