Effects of Undersized/Small Pulley Diameters


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      Belting suppliers and fabricators always list minimum pulley diameters in their catalogs and inquire to customers, relative to individual belt specs and components. Why is this so important?

      Undersized pulleys can create a number of issues — shortened belt life, ply separation, creation of stress cracks in covers, and cause cleats to lift from belt covers. The additional stress caused by an undersized pulley can also cause cracking of flanged edges, corrugated sidewalls, cleats and v-guides. Belting will also crack behind mechanical fasteners if the incorrect size or style is chosen.

      Under stress, the belt and components will look for the quickest/easiest path of least resistance to relieve the applied stress brought about by undersized pulleys. Remember: when selecting a fabricated belt, the “largest” minimum pulley diameter for each component must be chosen as the smallest pulley diameter to use.

      Lifting Cleat   Stress Cracks

      Trailing edge of a steep angle cleat lifting due to undersized pulley use.


      Stress cracks at the base of corrugated sidewalls running on small/undersized pulleys.

      Choosing the right belt for your application is important, and selecting the right components and accessories to go with it is just as critical.  Rely on the Apache’s belt experts to ensure you have the best product and the complete solution for your conveying needs.


      • By Tom Weisenstine, Vice President - Product Development

        December 11, 2013