Depending on the belt type and the manufacturer, metric V-Belt part number may specify different length measurements. The different belt lengths, abbreviations, and their relative positions in the belt are:
Gates classical Metric Power™ V-belts (e.g 10X, 13X, 17X) specify inside length in millimeters followed by”Li”. Narrow Gates Metric Power V-belts (e.g. SPZ, SPA, SPB, SPC) specify the datum/pitch length in millimeters.
Converting one length type into another may be required to identify if a proper replacement belt exists. The following table converts between any of the four length measurements. To find the correct equation, read the column headings across the top and choose the appropriate belt cross section. Read down the rows at the left and select the belt length type to calculate. Reading down the selected column and across the selected row, the box at the intersection lists the equations to convert from any of the other three length types.