Variable speed belts, just like timing belts, have their own special uses.  These belts are most commonly used on applications like Go-Karts and industrial applications like band saws or anything with a clutching system.  The angle on a variable speed belt is different than that of a standard v-belt which allows the clutching system of these applications to work properly.  The measurements that we will need to get you the proper belt are: Length of your belt and the width of your belt.