Disk drive including a balancing element with first and second cavities and a cylindrical portion disposed about a spindle motor hub

A disk drive comprising:

• a disk drive base;
• a spindle motor rotatably coupled to the disk drive base, the spindle motor including a spindle motor hub defining an axis of rotation;
• a disk disposed about the spindle motor hub, the disk including a disk inner diameter biased against the spindle motor hub at a contact location of the spindle motor hub;
• and
• a balancing element including:
• a cylindrical portion disposed about the spindle motor hub;
• a first cavity defining a first cavity centroid, the first cavity centroid disposed on a same side of the axis of rotation as the contact location;
• and
• a second cavity defining a second cavity centroid, the second cavity centroid disposed on a side of the axis of rotation opposite the first cavity centroid, the second cavity centroid being spaced apart from the first cavity centroid in a direction along the axis of rotation.