There are no hard and fast “expiration dates” on tires, but because rubber begins to crack and deteriorate over time, most experts suggest that eight years is the maximum safe life expectancy of a tire. If you don’t drive your classic at all and it just sits on display, you can get away with keeping the original tires as they’ll hold air. But if you drive the car at all, you need to know how old the tires are. The U.S Department of Transportation (DOT) requires that all tires manufactured since 2000 have serial numbers, and those numbers easily identify their age. Using the last four digits, the first two numbers will reveal the week and last two the year. For example, a serial number ending in 4905 tells you the tires were made during the 49th week of 2005. If there are no recognizable serial numbers, you already have your answer – the tires were made prior to 2000 and need to be replaced.