The National Highway Traffic Safety Administration filed a Supplemental Notice of Proposed Rulemaking (SNPRM) on new pneumatic tires for vehicles with a GVWR of more than 10,000 pounds to insert footnotes that have been absent since a revised rule was published in 1998.
FMVSS No. 119 was originally issued in 1967 to establish performance and marking requirements for tires for use on multipurpose passenger vehicles, trucks, buses, trailers, and motorcycles. Its purpose is to provide safe operational performance levels for these tires and to place sufficient information on the tires to permit their proper selection and use. FMVSS 119 adopted the strength test in FMVSS 109 from the Society of Automotive Engineers (SAE) Recommended Practice J918b—Passenger Car Tire Performance Requirements and Test Procedures. As part of the strength test, a plunger is driven into a tire. The tire must not be punctured before a minimum energy value is reached.
The tire strength test was designed to evaluate the strength of the reinforcing materials in bias ply tires, typically rayon, nylon, or polyester, and it continues to serve a purpose for these tires. NHTSA said bias tires have been almost completely replaced by radial tires in the U.S., but a small market for bias tires still remains.
The breaking energy requirements established in the SAE J918b tire strength test were higher for nylon and polyester cord tires than for rayon cord tires in order to ensure that the strength test stringency was comparable for different tire cord materials. As a result, when the FMVSS No. 119 strength test was established, Table II was accompanied by the footnote: “For rayon cord tires, applicable energy values are 60 percent of those in the table.”
But at the same time, while providing equivalent metric conversions and an additional footnote that the joules (J) measurements were rounded down to the nearest whole number, NHTSA omitted some static breaking energy values from the table as well as the two footnotes. NHTSA corrected the headings in a 2007 revision but not the footnotes. When the revision was repinted in the Code of Federal Regulations, the table values were printed incorrectly.
Then, in 2010, NHTSA issued an NPRM to upgrade FMVSS 119 but did not include changes to Table II with the proposed technical corrections. Last May, Continental Tire of the Americas questioned NHTSA about the omission, which resulted in the new SNPRM to reinstate the only the footnote on the applicable energy values for rayon cord tires because it was present in the original final fule. NHTSA explained it would not reinstate the footnote on rounding down J measurements to the nearest whole number because it no longer believes it is necessary.
