It is ten years and PLEASE find and highlight the date code with white paint or chalk or something before Tech. It's a PIA looking for date codes on everyone's tires!
The only exception not called out in the rulebook is "H" rated tires but you cannot exceed their speed rating (I think it's 130 MPH.) It's a good idea to replace tires after 10 years anyway even if you don't run that fast (I'm talking to myself here, lol.)
