HMK4030 Drawn Cup Needle Roller Bearing HMK 4030 gearbox Bearings HMK4030 is a Drawn Cup Needle Roller Bearing with open ends, featuring a thin - walled stamped outer ring and precision needle rollers. The open design allows easy lubriion and integration with adjacent components. It is optimized to handle heavy radial loads in compact spaces, with low friction enabled by the needle roller geometry. Sizes: 40mm ID x 50mm OD x 30mm Width = 1.5748" ID x 1.9685" OD x 1.1811"