NTEA
commonly receives questions on rerating commercial vehicle gross vehicle weight
rating (GVWR) and gross axle weight ratings (GAWRs). The following information
and resources can help provide a better understanding of the implications of
changing these ratings.
Jump to FAQs
Can a used vehicle be rerated?
How are vehicle ratings determined?
Can axles be added to increase GVWR?
What about lowering GVWR?
FAQs
Can a used vehicle be rerated?
- No. Certification
and ratings assignment apply only to new motor vehicles by the manufacturer(s)
during the initial build process. Once a vehicle has been completed in the
final stage and licensed and titled by an owner in a
given U.S. state, or sold and delivered to a purchaser at the first retail
level in a Canadian province or territory, the certification obligation ends,
along with assignment of ratings. In a 2002
interpretation, National Highway Traffic Safety Administration (NHTSA) provided
this
response to the concept of rerating used vehicles.
- National Highway Traffic Safety Administration (NHTSA) does not have
regulations or provisions for certifying a used vehicle, the process in which
ratings are assigned. Additionally, companies that change the original
GVWR/GAWRs of a used vehicle may face serious liability concerns.
How are vehicle
ratings determined (GVWR/GAWRs)?
- GVWR and
GAWRs are the maximum weights a new, completed vehicle and individual axles,
respectively, can bear and meet regulatory compliance requirements, durability
and OEM warranty objectives.
- Only the OEM
would know which components or limiting factors set these ratings, so it’s
important to consult the chassis manufacturer to determine if rating changes
are possible and to what extent on a new vehicle.
Can axles be
added to increase GVWR?
- It’s a
common misconception that GVWR can, or must, always be the sum of the GAWR
values.
- Even though
the chassis may have more axles than it did originally from the factory, it
does not mean it’s otherwise able to meet all brake system performance
requirements at a higher GVWR. Warranty coverage can also be affected by these
changes.
- OEM
incomplete vehicle documents (IVDs) often contain prohibitive language for
changing GVWR, preventing the intermediate-, final- and/or altered-stage manufacturer
from using OEM IVD guidance as a basis to certify the vehicle.
- The only
path forward is on a case-by-case basis. In determining feasibility of increasing
GVWR/GAWRs, the OEM would need to provide an engineering review and
documentation to support changing the original GVWR and/or GAWRs for a given
chassis. Otherwise, the intermediate,
final stage or altered stage manufacturer must determine compliance with all
applicable regulatory requirements.
What about lowering GVWR?
- There are a
number of potential pitfalls for both the manufacturers and motor carriers regarding
requests to derate GVWR on a new vehicle, and it cannot be assumed it’s
possible to do. These situations involve careful consideration and OEM guidance
before attempting to change OEM ratings.
- Lowering
GVWR could place the vehicle in a range where more regulatory compliance
requirements apply (for which the intermediate-, final- or altered-stage
manufacturer would become completely responsible).
- Rerating to 10,000
pounds GVWR or below requires proof the vehicle meets multiple
Canadian/Federal Motor Vehicle Safety Standard (C/FMVSS) crash test
requirements, destructive tests and dynamic tests — all of which the
company changing GVWR will be responsible to prove the modified vehicle
meets.
MORE RESOURCES
Disclaimer: This webpage and any related
resources are intended for informational purposes only, and should not be used
as a substitute for independent engineering analysis or judgment. This webpage
and any related resources are not, and are not intended to, constitute legal
advice or confirm legal compliance. To determine compliance with laws and
engineering standards, consult with your own legal counsel and engineering
experts.