How Do I Pack the Grease Into the Bottom Bracket Retainer Cages?

A bicycle's bottom bracket is installed in the frame cage in the bottom center of the bicycle frame. A bottom bracket has a set of sealed ball bearings and a spindle. When the cranks are attached to the spindle, power transfer takes place between the cranks and the chain and gears. There must be grease in the cage and bearings to keep the bottom bracket spinning smoothly. On mountain bikes, the cage and bracket are exposed to copious amounts of grit, mud and grime, making a repacking of the grease in the device and cage necessary about once a season.

Things You'll Need

  • Bicycle work stand (optional)
  • Bottom bracket tool
  • Bicycle grease
  • Rags
  • 8-millimeter hex wrench
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Instructions

    • 1

      Lean the bike against a post, or place it in a work stand. Pull the chain off the chain rings. Use the hex wrench to unscrew the cranks. Pull the cranks off the bicycle.

    • 2

      Insert the bottom bracket tool over the right-side cage, and check that the tool's jaws grip the bottom bracket cylinder. Turn the entire bottom bracket unit counterclockwise, and pull it out of the cage.

    • 3

      Wipe down the bottom bracket. Clean the threads around the cage on the bicycle frame using an old toothbrush and rags.

    • 4

      Smear a generous portion of grease over the threads on the cage, on the left- and right-hand sides of the cage.

    • 5

      Pack the bearing rings on the left- and right-hand sides of the bottom bracket with grease by placing grease around the bearing cartridge and tapping it in with your fingers. Some bottom brackets are closed and do not require repacking of the grease. If you are unsure whether your bottom bracket is closed, look to see if there are exposed sections of the outer rings where the bearings are exposed. If so, you have a bottom bracket that needs repacking. If you cannot see the bearings, it is closed.

    • 6

      Install the bottom bracket back into the cage using the bottom bracket tool. Turn the unit clockwise to lock it into the bicycle frame's cage.

    • 7

      Screw the cranks back onto the bottom bracket spindle using the hex wrench. Thread the chain back over the chain ring.