Rekeyable lock cylinder

A rekeyable lock cylinder comprising:

• a plurality of first rack components;
• a plurality of second rack components selectively engaged with the first rack components and movable via contacting against a first matched key which is inserted in a first direction, when the first matched key is inserted in the rekeyable lock cylinder;
• and
• a guide bar having a first surface engaged with the first rack components, a second surface opposite to the first surface, a first side in connection with the first surface and the second surface, a second side in connection with the first surface and the second surface, and a tool-receiving portion recessed into the first side, wherein the second surface is formed in a smooth shape, the tool-receiving portion is parallel to the first direction, and the first rack components are actuated by said guide bar via acting force applied by a rekeying tool accommodated in the tool-receiving portion, when the rekeying tool is inserted in the tool-receiving portion, therefore enabling the first rack components to move in a transverse direction relative to the first direction and disengaging the first rack components from the second rack components.