Tyre Size Example Example: 215/60R15 215 is the width of the tyre in millimetres. 60 is the aspect ratio or tyre profile. • R means it is radial construction. 15 is the diameter of the wheel rim in inches. Along with the manufacturer’s name and the name of the tyre (e.g. Bridgestone Ecopia), there’s always … Continue reading How to read your tyre size