If the center distance of sprocket drive is too small, the packing angle on sprocket is small, and the number of teeth of sprocket meshing at the same time is less. If the center distance is too large, the chain will shake easily. Generally, the center distance is a=(30-50)p, and the maximum center distance is less than or equal to 80p.

The length of the chain is represented by the number of nodes in the chain. According to the formula to find the length of the belt drive, the number of chain segments calculated by the formula should be rounded to be an integer, preferably an even number. The formula of center distance a can be solved by using the above formula: in order to facilitate the installation and adjustment of chain tension, the center distance should be designed to be adjustable or there should be a tensioning device.