How to Service a Shimano Three-Piece Crank

Cranks and chainrings, the large toothed rings attached to the cranks, get gummed up and grimy over time. Grime and grit get into the housings and impedes chain movement and causes gear misfires when shifting. These problems can be taken care of by cleaning and servicing the cranks. Shimano cranks and chainrings get serviced using degreasers, rags and brushes.

Things You'll Need

  • Wire brush or old toothbrush
  • Degreaser
  • Small drip pan
  • Shop rags
  • Chain lubricant
  • Allen keys
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Instructions

    • 1

      Pour the degreaser into the drip pan. Unscrew the chainrings from the cranks using the Allen keys.

    • 2

      Slide the large chainring of the crank spline and place it into the degreaser. Slide the middle chainring of the crank spline and put in the degreaser with the large chainring.

    • 3

      Dip the wire brush or toothbrush into the degreaser and scrub off the grease and grime from the smallest chainring while still connected to the cranks. Scrub the crank splines and the connecting bottom bracket -- the square-shaped rod protruding from the center of the frame.

    • 4

      Wipe off excess degreaser from the cranks and small chainring with the rags. Pull the two chain rings out of the degreaser and wipe down with the rags. Attach the chainrings back to the cranks using the Allen keys.

    • 5

      Turn the bicycle upside down and place on the seat and handlebars. Turn the cranks to spin the chain and gears. Pour lubricant onto the cranks, chainrings and chain. Let the lubricant soak into the mechanisms.