Interpretation ID: 77-2.48
TYPE: INTERPRETATION-NHTSA
DATE: 06/09/77
FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA
TO: TTMA
TITLE: FMVSS INTERPRETATION
TEXT: This responds to your March 16, 1977, letter in which you ask for an interpretation of the certification label requirements of Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars, as they apply to trailers.
In your first question, you ask whether a trailer manufacturer may conform with the certification requirements in any one of three ways: list the GVWR and GAWR with the corresponding tires, rims, and inflation pressure with which the trailer is equipped; list all suitable combinations with the required information as shown in the example appearing in Standard No. 120; or list only the maximum GVWR and maximum GAWR with the proper tires, rims, and inflation pressure, plus the GVWR and GAWR of the trailer with the tires, rims, and inflation pressure with which it is equipped. According to the requirements of Standard No. 120, any of the three methods outlined above would appear to be acceptable.
Your second question presents a sample certification plate which lists all of the axles on the trailer. You ask whether it is permissible, where the data for all axles is identical, to list the proper tires, rims, and inflation pressure for the front axle then merely state "Same as Front" for the remaining axles rather than repeat the same data for all axles. The label requirements of the standard do not permit the approach you suggest. You must list all data for each axle. You should note that there is a proposal to amend Part 567, Certification, to permit a simplification of label requirements when the data for all axles is identical. I am enclosing a copy of this proposal for your information.
SINCERELY,
Truck Trailer Manufacturers Association
March 16, 1977
Fred Koch Office of Crash Avoidance National Highway Safety Administration
S. 120 - Tire Clarification
It is our understanding that if a trailer manufacturer has several tire options for a trailer model, such as 10.00 x 20, 10.00 x 22, and 10.00 radial x 22, then he may note this at least three different ways on the certification label per S. 120.
(a) He may list the GVWR and the corresponding GAWR with the tires, rims, and inflation pressure as the trailer is equipped. That is, he may have three labels to choose from, depending on the tires selected by the purchaser.
(b) He may list the GVWR and the corresponding GAWR with the tire, rims, and inflation pressure for each option as shown in the example in S. 120.
(c) He may list the maximum GVWR and the corresponding maximum GAWR with the tires, rims, and inflation pressure yielding the maximum rating and the GVWR and the corresponding GAWR with the tires, rims, and inflation pressure for the trailer as equipped.
Since some European tire manufacturers do not use the "R" in their tire size designation to indicate radial it is understood that the trailer manufacturer may add the note that the stated inflation pressure is for radial tires.
It is also our understanding that where all axles on a trailer are similar, that the certification plate may state:
GVWR: x x x x
GAWR: Front - x x x x with x x x x tires, x x x rims, at xx psi cold dual.
First Intermediate - Same as Front
Second Intermediate - Same as Front
Rear - Same as Front
Please inform us if our understanding of S. 120 is correct.
Don W. Vierimaa Engineering Manager
cc: TTMA ENGINEERING COMMITTEE