Originally Posted by 70sSanO

I have cranks with self extracting bolts. Pretty simple design.

Basically you are using an allen/hex head crank bolt with a wide shoulder. Torque the bolt and then thread in the dust/extractor cover “all” the way in with a pin spanner. The cover allows access to the crank bolt. When you want to remove the crank, loosen the crank bolt and the force against the extractor cover as the crank bolt is threaded out pulls the crank.

John