Tyre sizes are defined by 3 numbers – the height, the width and the rim size in that order. All sizes are given in inches and will be stamped on the side wall of the tyres currently fitted to your machine. In order to select the correct tyre for your vehicle, you will need the wheel rim size (in inches), which is the last number listed. You can then chose a height and width.
It is recommended that you keep the tyre height the same or close to the original size, unless you have a special application, in order to keep the gearing the same. Width can be varied to give more (or less) traction, but check that the larger tyre can be accommodated without touching the frame or bodywork. So remember – height x width x wheel diameter.
Please note that many of the items on sale are shop stock and may show signs of storage in a dusty workshop!