[wiredgeorge]

The date code mentioned is critical. Since you didn't notice the different brands and sizes you probably don't know how to determine the tire's manufacture date. There is a small oval on the side of the tire. It has four numbers. First two numbers are the week within a year and second two numbers are the year. Thus, a date code 2715 means 27th week of 2015 manufacture date. When buying new tires (which you probably should) check the date code as some may have been on a shelf for a LONG time before being sold to you.