How do you know when your tires need to be replaced?

Most original equipment tires have wear indicator bars that will appear when your tread depth reaches a predetermined limit, usually 1/16 inch. It can be monitored with a tool called a tread depth indicator, or a penny placed head down into the tread, when the tread reaches the top of Lincolns head they are ready to be replaced. Look for unusual wear patterns like cupping, flat spots, and more wear on one side more than another as these indicate an suspension or balance issue that must be corrected.