I recently handled a personal injury case where the Defendant purchased used tires for his vehicle. The tires looked new based on the tread depth. However, what the Defendant did not know was that the tires were 10 years old. They had simply been kept in storage. As the Defendant was driving the vehicle on the interstate, the tire suddenly blew out. The Defendant lost control of the vehicle and a major wreck ensued involving multiple vehicles and multiple injuries.

Most of the big tire manufacturers like Goodyear and Bridgestone do not place an age limit on tires. However, many car manufacturers recommend that tires should be discarded after 8 years regardless of amount of tread on the tire.
The reasoning is fairly simple when you think about it. Tires are made from rubber. Over time we all know that rubber begins to breakdown in a process that we typically call dry rot. When the rubber from the tire breaks down and dries out over time, it weakens the tire. The added heat and stress that occurs when a tire is being operated at a high speed on an interstate highway provides that perfect storm to cause a major blowout.

I see used tires being sold more and more over the last few years. I am all for saving money but when it comes to the safety of your family, please spend the extra for new tires.