The size 265/45 R21 is reserved for tyres designed for sports vehicles. The first number (265) is a tyre's tread width expressed in millimetres. The next number is a designation of the tyre's profile height expressed in percentage (45% out of 265 millimetres of the tyre's tread width). The "R" in tyre's size means that the tyre is built in a radial construction. Last parameter in the tyre's size is the diameter of the wheel's rim (in inches) on which the tyre can be installed. With us you will make the best purchase of the tyres in size 265/45 R21.