Widi is roller bearings manufacturer and supplier. Roller bearings — also known as rolling-element bearings — are similar to ball bearings in that they are designed to carry a load while minimizing friction. However, roller bearings transmit loads using cylinder rolling elements, rather than balls, to maintain the separation between moving parts of the bearing. These bearing systems use the decrease in rolling resistance as a means of increasing the efficiency of moving an object. Roller bearings typically fall within three categories: cylindrical, tapered, and needle.