Ships From Sydney - 500EX Key Hub

This is the "500EX Key Hub". It is a slightly different version of the 500 Key Hub. It is manufactured differently, as it is extruded. Also, there is a 1.124" diameter boss on each side of the hub flange, providing a location for 1.125" bore flat sprockets. Are you having a hard time keeping your sprocket concentric with your hub? This hub is the trick.

The bore is a 1/2" hole with two 1/8" keyways. Only one keyway is needed to drive most wheels, so the second one is extra.

Also, the keyways are consistently aligned with the mounting holes.