Tyre (tire) Regulatory Markings
In the United States, the DOT Code is an alphanumeric character sequence molded into the sidewall of the tire for purposes of tire identification. The DOT Code is mandated by the U.S. Department of Transportation. The DOT Code is useful in identifying tires in a product recall.
The DOT Code begins with the letters "DOT" followed by a plant code (two numbers or letters) that identifies where it was manufactured. The last four numbers represent the week and year the tire was built. A three-digit code was used for tires manufactured before 2000. For example, 178 means it was manufactured in the 17th week of 8th year of the decade. In this case it means 1988. For tires manufactured in the 1990s, the same code holds true, but there is a little triangle (Δ) after the DOT code. Thus, a tire manufactured in the 17th week of 1998 would have the code 178Δ. In 2000, the code was switched to a 4-digit code. Same rules apply, so for example, 3003 means the tire was manufactured in the 30th week of 2003.
Other numbers are marketing codes used at the manufacturer's discretion.
All tires sold for road use in Europe after July 1997 must carry an E-mark. The mark itself is either an upper case "E" or lower case "e" – followed by a number in a circle or rectangle, followed by a further number. An (upper case) "E" indicates that the tire is certified to comply with the dimensional, performance and marking requirements of ECE regulation 30. A (lower case) "e" indicates that the tire is certified to comply with the dimensional, performance and marking requirements of Directive 92/23/EEC. The number in the circle or rectangle denotes the country code of the government that granted the type approval. The last number outside the circle or rectangle is the number of the type approval certificate issued for that particular tire size and type.
Mold serial number
Tire manufacturers usually embed a mold serial number into the sidewall area of the mold, so that the tire, once molded, can be traced back to the mold of original manufacturer.
Sound and vibration characteristics
The design of treads and the interaction of specific tire types with the roadway surface type produces considerable effect upon sound levels or noise pollution emanating from moving vehicles. These sound intensities increase with higher vehicle speeds. The acoustic intensity produced varies considerably depending on the tire tread design and the road surface type. There is a study "under development" that aims predict the interior noise due to the vibrations of a rolling tire structurally transmitted to the hub of a vehicle".
The United States Department of Transportation (DOT) is the U.S. governmental body authorized by the U.S. Congress to establish and regulate transportation safety in the United States of America.
The National Highway and Traffic Safety Administration (NHTSA) is a U.S. government body within the Department of Transportation tasked with regulating automotive safety in the United States.
The Uniform Tire Quality Grading System (UTQG), is a system for comparing the performance of tires, established by the United States National Highway Traffic Safety Administration according to the Code of Federal Regulations 49 CFR 575.104. The UTQG regulation requires labeling of tires for tread wear, traction, and temperature.
The Tire and Rim Association (T&RA) is a voluntary U.S. standards organization to promote the interchangeability of tires and rim and allied parts. Of particular interest, they published key tire dimension standards, key rim contour dimension standards, key tire valve dimension standards, and load / inflation standards.
The European Tyre and Rim Technical Organization (ETRTO) is the European standards organization "to establish engineering dimensions, load/pressure characteristics and operating guidelines" . for tires, rims and valves. It is analogous to T&RA.
The Japanese Automobile Tire Manufacturers Association (JATMA) is the Japanese standards organization for tires, rims and valves. It is analogous to T&RA and ETRTO.
The Transportation Recall Enhancement, Accountability and Documentation Act (TREAD Act) is a United States federal law that sets standards for testing and the reporting of information related to products involved with transportation such as cars and tires.
Radio Frequency IDentification tags (RFID) are passive transponders affixed to the inside of the tire for purposes of automatic identification. Tags are encoded with various types of manufacturing data, including the manufacturer's name, location of manufacture, tire type, manufacturing date, and in some cases test data. RFID transponders can remotely read this data automatically. RFID tags are used by auto assemblers to identify tires at the point of assembly to the vehicle. Fleet operators utilize RFID as part of tire maintenance operations.
CCC (China Compulsory Certification) is a mandatory certification system concerning product safety in China that went into effect in August 2002. Before CCC, there were two certification systems in China: CCIB and CCEE. With China's entrance into the WTO, these two systems were unified into the CCC certification system. After the termination of a one-year grace period in August 2003, the system became compulsory.The CCC certification system is operated by the State General Administration for Quality Supervision and Inspection and Quarantine of the People's Republic of China (AQSIQ) and the Certification and Accreditation Administration of the People's Republic of China (CNCA).
Proper vehicle safety requires specific attention to inflation pressure, tread depth, and general condition of the tires. Over-inflated tires run the risk of explosive decompression (they may pop). On the other hand, under-inflated tires have a higher rolling resistance and suffer from overheating and rapid tread wear particularly on the edges of the tread. Excessive tire wear will reduce steering and braking response,and tires worn down past their safety margins and into the casing run the very real risk of rupturing. Also, certain combinations of cross ply and radial tires on different wheels of the same vehicle can lead to vehicle instability, and may also be illegal. Vehicle and tire manufacturers provide owners' manuals with instructions on how to check and maintain tires.