Tire Identification and Recordkeeping; Tire Identification Symbols

NHTSA's tire identification and recordkeeping regulation requires new tire manufacturers and tire retreaders to mark a tire identification number on one sidewall of each tire they produce. The number is composed of the manufacturer's or retreader's identification code, a tire size symbol, an optional descriptive code, and the date of manufacture, which includes the date of retreading. The date is reflected in the last 3 digits of the number. In response to petitions for rulemaking, the agency is amending the regulation to require the date to be expressed in 4 digits instead of the currently required 3, and to reduce the minimum size of the digits from the currently required minimum of 6 millimeters (mm) (\1/4\ inch) to 4 mm (\5/32\ inch). The 4-digit date code will permit better traceability of tires during recalls and allow easier identification of older tires. Reducing the size of the date code from 6 mm to 4 mm will relieve manufacturers and retreaders of the burden they might otherwise incur by having to redesign their tire molds to accommodate the additional digit, without significantly affecting the readability of the date code digits. Finally, these amendments will enhance harmonization by bringing the U.S. tire date code requirements into harmony with the new United Nations' Economic Commission for Europe regulation and the International Organization for Standardization recommended practice.