Interpretation ID: aiam3191
Engineering Manager
Technical Information Department
Michelin Tire Corporation
One Marcus Avenue
Lake Success
New York 11042;
Dear Mr. White: This responds to your November 16, 1979, letter in which you requeste an interpretation of the requirements of Federal Motor Vehicle Safety Standard No. 109 (49 CFR S571.109). Specifically, you asked if it is permissible for a tire manufacturer to label its tires with information about other tire sizes which the labeled tire could be used to replace. For example, you stated that Michelin would like to label its tires with the alphanumeric tire size which its P-metric tire sizes could replace and that Michelin would like to label its 230-15 tires as replacements for the 225-15 tires. Such labeling is expressly prohibited by Standard No. 109.; Paragraph S4.3(a) of Standard No. 109 specifies that each tire shall b labeled with '*one* size designation, except that equivalent inch and metric size designations may be used.' With respect to the alphanumeric sizes and the P-metric replacements and the 225-15 and 230-15 sizes, the suggested replacements sizes have different section widths and minimum size factors than the sizes they would be replacing. In other words, they are not equivalent size designations, and S4.3(a) prohibits the tire from containing more than one size designation in these circumstances.; Labeling of the sort you have requested has been commonly referred t as 'dual-size markings.' Dual-size markings are a representation that a particular tire can be considered as meeting fully the criteria of two separate tire size designations. In fact, such tires do not satisfy the physical dimension criteria in Standard No. 109 for both size designations. As a consequence, labeling of this type was specifically prohibited when the labeling requirements o Standard No. 109 were amended at 36 FR 1195, January 26, 1971. The prohibition has been repeated in subsequent notices which addressed the question of tire labeling under the Standard, *see* 39 FR 10162, March 18, 1974 and 42 FR 12869, March 7, 1977.; I should note that prohibition of dual-size markings does not mean tha NHTSA believes that the replacement tires would perform inadequately if installed on the rims. However, dual-size markings represent a marketing effort by tire manufacturers to attempt to persuade consumers to change the size and/or type of tires mounted on their cars. It is inappropriate to extend this marketing effort to the Federally required label on the tire. The manufacturer must provide the consumer, in a straightforward manner, technical information necessary for the safety of the consumer's automobile. This should be the only purpose of the label.; Sincerely, Frank Berndt, Chief Counsel