Repair guides › Drivetrain

Replace external-cup BB

Bearings sit in cups outside the shell for a fat hollow spindle. Threaded cups; drive side reverse threaded.

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Tools

• Ball-end hex key set (1.5–10 mm): Park Tool HXS-1.2 Professional L-Shaped Hex Set ($$)
• 1/4" click torque wrench (about 2–17 Nm) + bits: Pro Bike Tool 1/4 inch drive click torque wrench set (2.2–16.9 Nm) ($$)
• Bike grease: Park Tool PPL-1 PolyLube 1000 ($)
• 3/8" click torque wrench 10–60 Nm: Pro Bike Tool 3/8 inch Drive Click Torque Wrench Set 10-60 Nm ($$$)
• External BB wrench + crank cap tool: Park Tool BBT-9 + Shimano TL-FC16 ($$)

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Steps

1. Remove cranks.
2. Unscrew cups (drive side clockwise).
3. Grease threads, install with correct spacers.
4. Torque 35–50 Nm.

Diagram

Signs it needs doing

• Rough spin
• Creak

Problems this fixes

• Clicking or ticking when pedaling
• Creaking when climbing or pedaling hard
• Pedal or crank feels loose or wobbly