Interpretation ID: aiam4383
Manager
Truck Engineering
MMC Services
Inc.
3000 Town Center
Suite 501
Southfield
MI 48075;
Dear Mr. Osaki: This responds to your letter asking about the relationship between th maximum load ratings for the tires on a medium duty truck and the gross vehicle weight rating (GVWR) specified for that truck pursuant to 49 CFR Part 567, *Certification*. Specifically, you asked if the GVWR specified for a truck could slightly exceed the sum of the gross axle weight ratings specified for the truck. While none of our regulations prohibit your company from assigning a GVWR that exceeds the sum of the gross axle weight ratings for this medium duty truck, we recommend that you not do so, for the reasons explained below.; Your letter correctly notes that paragraph S5.1.2 of Standard No. 120 *Tire Selection and Rims for Motor Vehicles other than Passenger Cars* (49 CFR S571.120) requires that the sum of the maximum load ratings of the tires fitted to each truck axle shall be not less than the gross axle weight rating (GAWR) for the axle system, as specified on the vehicle certification label required by Part 567. However, Part 567 does not limit the GVWR that can be assigned to the sum of the GAWR's specified for a vehicle. Instead, S567.4(g)(3) requires that the vehicle certification label specify the GVWR of the truck and requires only that the specified GVWR 'shall not be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity.'; Although Part 567 does not prohibit such a practice, we note tha assigning a GVWR to a vehicle that exceeds the sum of the GAWR's assigned to the vehicle (other than a semitrailer) would be encouraging the user of that vehicle to overload it. If the axles of a medium duty truck cannot safety bear the load specified in the GVWR, the vehicle will be overloaded whenever it is loaded to the specified GVWR. Such overloading poses a serious safety hazard for the affected vehicle in particular and for the motoring public in general. Several past interpretations on this subject have stated if a vehicle suffers a hazardous malfunction while in use that can be traced to the overloading of its axle systems, its manufacturer may be liable both under the defect provisions of the National Traffic and Motor Vehicle Safety Act and under common law product liability doctrines. To avoid giving rise to a potential safety hazard and the accompanying liability, we recommend that you specify a GVWR not greater than 17,196 pounds for the medium duty truck in question.; Sincerely, Erika Z. Jones, Chief Counsel