3.12 drivetrain

Bottom Bracket Removal — External Cup (Hollowtech II / GXP / similar)

Bottom Bracket Removal — External Cup (Hollowtech II / GXP / similar). Step-by-step procedure for bike maintenance — tools, time, and what to watch out for.

Difficulty ★★★ advanced
Time ~20 min
Applies to Bikes with threaded external-cup BB (most Road, Gravel, MTB)

Tools

  • BB tool matched to your cup splines (Park BBT-9 or BBT-79)
  • torque wrench

Procedure

  1. Remove the crankset first

    (3.10).

  2. Identify cup direction:

    Most threaded BBs have **English / BSA** threading. The drive-side cup is **reverse-threaded** (loosen clockwise viewed from the drive side); non-drive is standard (loosen counter-clockwise viewed from the non-drive side). **Italian** threaded BBs are standard threading on both sides.

  3. Engage the BB tool into the cup splines.

    The fit should be tight; loose engagement will round the splines.

  4. Apply force

    with a long wrench. BBs can be very tight — penetrating oil helps if it's stuck.

  5. Unscrew both cups

    and remove from the BB shell.

  6. Clean and inspect the BB shell threads.

    Wipe out any old grease, water, or debris. ---

Procedure #

  1. Remove the crankset first (3.10).
  2. Identify cup direction: Most threaded BBs have English / BSA threading. The drive-side cup is reverse-threaded (loosen clockwise viewed from the drive side); non-drive is standard (loosen counter-clockwise viewed from the non-drive side). Italian threaded BBs are standard threading on both sides.
  3. Engage the BB tool into the cup splines. The fit should be tight; loose engagement will round the splines.
  4. Apply force with a long wrench. BBs can be very tight — penetrating oil helps if it’s stuck.
  5. Unscrew both cups and remove from the BB shell.
  6. Clean and inspect the BB shell threads. Wipe out any old grease, water, or debris.