Simson Crank puller for disassembling the crank (the pedals are mounted on this part) of the crankshaft. First, remove the lock nut from the crank. Screw the crank puller firmly in the thread of the crank. Then turn the inner bolt of the crank with a socket wrench towards the bottom bracket. The crank comes so gradually from the bottom bracket. The crank is gently separated from the crankshaft.