How to Tighten a Bottom Bracket Cup

Older bicycles may be equipped with a cup and cone style bottom bracket. These bottom brackets thread through the bottom center of the bicycle frame, housing the spindle to which the crank arms and cranks are attached, thus allowing the pedaling motion. If you have lateral slop in the bottom bracket equipped with the cup and cone, the cup needs to be tightened. Lateral slop is when the cranks move out from the bottom bracket instead of remaining completely parallel to the bicycle frame. Tightening the cup brings the cranks and arms back into the bicycle, making pedaling safer and efficient.

Things You'll Need

  • Bicycle lock ring wrench
  • Rubber mallet
  • Rag
  • Bike work stand (optional)
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Instructions

    • 1

      Place the bicycle next to a tree, post, or solid object. Alternately, if you have a bicycle workstand, place it in the stand.

    • 2

      Open the lock ring wrench so the two tines are apart and slip it into the gap between the crank arms and the bicycle frame. Place the tines onto one of the cup attachment points and grip tight on the two handles of the lock ring wrench.

    • 3

      Press down on the lock ring wrench handles. If the handles are difficult to move, as they often are, wrap them in a rag and gently tap on them with a rubber mallet. Turn the bottom bracket cup clockwise to tighten the cup. Look straight at the bottom bracket to get the clockwise perspective.

    • 4

      Pull the tool out of the gap and set it aside. Grip the two crank arms and jostle them side to side, feeling for any lateral slop. If the slop is gone, hop on the bike and ride on.

    • 5

      Place the lock ring wrench back onto the gap and continue to tighten until the slop is out of the crank arms. Again, tighten in the clockwise direction.