Simplicity 1729578SM  Ball Bearing, 3/4" ID X 1-3/4" OD X 5/8"

The purpose of the Bearing is to reduce friction between parts while allowing motion in the desired direction. Common uses for a bearing are to support rotating shafts, like the axles moving the wheels, the spindles spinning the blade, or the crankshaft within the engine. When bearings fail, the increase in heat, pressure, and metal-on-metal contact can damage or destroy other parts. Some types of bearings are unsealed and can lose grease, adding more grease can be key to maintaining proper operation.