Tire manufacturing date codesThe following was extracted from our RV Glossary Of Terms, compiled and edited by forum staffer Don Jordan.
Generally accepted rules of thumb in the RV world are that, regardless of low mileage or low tread wear, tires should be replaced every 5 to 7 years maximum. Exposure to sunlight, ozone, and ultra-violet radiation causes gradual loss of the plasticizers that keep the tires flexible. Sidewall cracking can often be seen but may not always be apparent. So, for safety’s sake and to avoid sudden catastrophic failure, replacement should be done on an age priority basis. This does not mean that obvious tread wear, sidewall damage, or any other physical problem with the tires should be ignored if they still have “x” years to go before they are “too old”.
The National Highway Traffic Safety Administration (NHTSA) Tire Identification and Record Keeping Regulation, revised July 2, 2000, specifies a new 4-digit date code that must appear on all tires sold in the United States. The complete DOT (Department of Transportation) code is in the following format: DOT MMM SS TTT DDDD where MMM is a 3 digit manufacturer ID; SS is a tire size 2 digit code; TTT is an optional tire type code; and DDDD is the date of manufacture code where the first 2 digits indicate the week of manufacture and the second two digits are the year, i.e. 2802 would indicate that the tire was manufactured the 28th week of 2002.
Note: tires manufactured before July 2, 2000 had a 3 digit date code where the first 2 digits are the week of manufacture and the last digit is the year. Tires manufactured in the 1990’s had a triangle following the 3 digit code, while tires manufactured in the 1980’s did not. i.e. 282 with a triangle would indicate that the tire was manufactured the 28th week of 1992 while if there is not a triangle following the 3 digits it was manufactured in the 28th week of 1982. The newer 4-digit code eliminates any ambiguity in the year of manufacture and allows continuation of the system through the 21st century.
It is strongly recommended that when buying new tires you insist on all tires having the same date of manufacture and that that date should not be more than a few months prior to the date of purchase. Otherwise you will be buying tires that will need to be replaced sooner than necessary.