hub is part of:
    80%  wheel
    50%  car
    40%  round
    32%  circular  (indirectly)
    20%  cylindrical  (indirectly)

hub contains:

Full expansion for hub:
   100%  Large Tiny-Peg Hub
   100%  Small Tiny-Peg Hub
   100%  2x2 Studded Hub w/ Metal Peg
   100%  2x2 Studded Hub w/ Peg Hole
   100%  2x2 Technic Cross-Axle Hub
   100%  4x4x1.3 Grooved Hub w/ 7 Peg Holes
   100%  4x4x1.6 Grooved Hub w/ 7 Peg Holes
   100%  4x4x2 Cylinder Hub w/ 6 Peg Holes
    90%  3x3 Technic Wheel Hub/Tri-Pulley
    80%  Large Tiny-Peg Hub w/ Treaded Tires
    80%  Small Tiny-Peg Hub w/ Thin Tires
    80%  Small Tiny-Peg Hub w/ Treaded Tires
    80%  Small Tiny-Peg Hub w/ WideFlat Tires
    80%  2x2 FreeStyle Hub w/ Large Tires
    80%  2x2 FreeStyle Hub w/ Small Tires
    80%  2x2 Plate w/ Tiny Gray Wheels
    80%  2x2 Spoked Hub w/ Treaded Tires
    80%  2x2 Technic Cross-Axle Hub w/Lg.Tires
    80%  2x2 Technic Cross-Axle Hub w/Sm.Tires
    80%  2x4 Brick w/ Red 2x2-Stud End Hubs
    80%  3x3 Technic Hub w/ "30.4x14 VR" Tire
    80%  3x3x2 10+10-Tooth Tank-Tread Hub
    80%  4x4 Technic Hub w/ "13x24" Tire
    80%  4x4 Technic Hub w/ "43.2x28 S" Tire
    80%  4x7 Car Chassis w/ Tires & Hubs
    80%  5x5 Technic Hub w/ "20x30" Tire
    80%  5x5 Technic Hub w/ "49.6x28 VR" Tire
    80%  5x5 Technic Hub w/ "68.8x40 Q" Tire
    50%  3x3 Technic Pulley w/ Tires
    10%  3x3 Technic Pulley