How to Remove Bicycle Crank Bearings

That screeching noise coming from the cranks on your bicycle is a sign that the ball bearings in your bottom bracket might need cleaning or changing. In order to remove the bearings from your crankset, it is necessary to overhaul your bottom bracket. The bottom bracket holds the two crank arms on your bike together and secures them to the frame. Inside the bracket, the bearings surround a rotating spindle that allows you to turn the cranks independently of the frame.

Things You'll Need

  • Crank Puller
  • 17mm Adjustable Wrench
  • Bottom Bracket Wrench
  • Hooked Lockring Wrench
  • Cleaning Solvent
  • Waterproof Grease
  • Cleaning Cloth
  • Toothbrush
  • Cup
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Instructions

  1. Removing the Bearings

    • 1

      Remove the cranks using a crank puller and a 17 mm open-end wrench.

    • 2

      Loosen and remove the lockring on the left side by turning it clockwise with a hooked lockring wrench. Turn the right side bearing race counter-clockwise with a bottom bracket wrench to remove it. Note that several bottom bracket designs have the lockring on the right side. In either case you must remove the lockring-side bearing race before you can remove the spindle and the other bearing race.

    • 3

      Remove the spindle. When you pull it out, you might pull out the bearing cages as well. If not, they will come out with the bearing races. Remove the left side bearing race by turning it clockwise.

    Bearing Maintenance or Replacement

    • 4

      Wipe off the bearing races with a cloth and determine whether they need to be changed. If the bearings and the cages show no wear, they only need cleaning. If the bearings are worn, replace them.

    • 5

      Clean the bearing cages with a toothbrush and cleaning solvent. Then drop the bearing cages into a cup containing cleaning solvent.

    • 6

      Clean the spindle, lockring and bearing races with a cloth and cleaning solvent. Then clean and regrease the threads on the inside of the bottom bracket housing.

    Replacing the Bottom Bracket

    • 7

      Apply grease to the insides of the bearing races and the bearing cages. Make sure that you thoroughly grease the bearing cages by applying a thin layer of grease between each ball bearing.

    • 8

      Place the bearing cages rounded side down into the bearing races. Apply another layer of grease to seal them in.

    • 9

      Using the bottom bracket wrench, twist the left side bearing race into the bottom bracket housing by turning it counter-clockwise. Twist the lockring on but do not tighten it very much at this time. Insert the spindle as you removed it. The right side of the spindle should be slightly longer than the left side.

    • 10

      Slide the right side bearing race onto the spindle and tighten by turning it clockwise. Wipe off any excess grease and turn the spindle to make sure that it spins with no interference.

    • 11

      Reinstall the right side crank arm and tighten it. Adjust the bearing tightness by holding the left bearing race with the bottom bracket wrench and tightening the lockring with the hooked lockring wrench. If the spindle doesn't spin smoothly, you may need to tighten or loosen the bearing race. Remember to loosen the lockring before adjusting the bearing race and to tighten it afterwards.

    • 12

      Reinstall the left crank arm. Pull and push on both cranks to make sure that they are firmly attached to the spindle. You may need to tighten the cranks if they move in any direction other than a spin.