We are finding a small-molded triangle at the end of the date code marking on some of the casings we receive for retreading. It only shows up on some of the casings with a three-number date code and n

This triangle means the tire was manufactured in the 90's. At that time, having the triangle was not required, so you will find some tires manufactured in the 90's that do not have the triangle. Since all tires manufactured today are required to have a four-number date code, the triangle is no longer used.