Interpretation ID: nht76-3.20

DATE: 01/15/76

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Wenke; Burge; and Taylor

TITLE: FMVSR INTERPRETATION

TEXT: I am writing in response to questions you raised in a January 7, 1976, telephone conversation with Mark Schwimmer of this office, concerning the determinations of Gross Vehicle Weight Rating (GVWR) and Gross Axle Weight Rating (GAWR) for a boat trailer.

GVWR is defined as:

the value specified by the manufacturer as the loaded weight of a single vehicle. (49 CFR 571.3).

One constraint on this specification is found in the Certification regulation, which requires that the GVWR be

not less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity . . . . (49 CFR 567.4(g)(3))

"Rated cargo load" is not defined. If a manufacturer does not provide a cargo load rating to dealers or consumers, the NHTSA expects his determination of GVWR to reflect a good faith evaluation of the vehicle's load carrying capacity. In the case of a boat trailer, this evaluation should be made with the assumption that the trailer is attached to a towing vehicle and should include that portion of the trailer's load that is carried by the towing vehicle.

GAWR, on the other hand, is defined as:

the value specified by the vehicle manufacturer as the load carrying capacity of a single axle system, as measured at the tire-ground interfaces.

The GAWR of a boat trailer's axle system could thus be less than the GVWR, because some of the trailer's load would be carried by the towing vehicle. However, the NHTSA would consider a boat trailer with a GAWR that is less than the actual load on its axle system, when loaded to its GVWR and attached to a towing vehicle, to contain a safety-related defect, which is subject to the notification and remedy requirements of the National Traffic and Motor Vehicle Safety Act of 1966.

The NHTSA expects to issue, in the near future, Federal Motor Vehicle Safety Standard No. 120, Tire and rim selection for vehicles other than passenger cars (49 CFR 571.120). Until the effective date of that standard, however, we will continue to consider a vehicle with tires insufficient for its gross axle weight ratings to contain a safety-related defect.