How to change your external bottom bracket cups?
Change your Road or MTB external bottom bracket cups is not difficult and requires only one specific tool: a bottom bracket spanner.
Typical tools: 5mm Hex Wrench / Bottom Bracket spanner / Mallet / Grease
Loosen the two left crank pinch bolts and remove arm cap.
Lift the stop plate upwards with a screwdriver.
Pull off left arm.
Remove the chain from the chainring. Pull crankset to right to remove right arm. It's sometimes necessary to gently tap with mallet.
Unthread left side cup (Non-drive side) counterclockwise.
Unthread right side cup (drive side) clockwise.
Get the grime out and grease thread.
Install correct spacers as needed (68mm bottom bracket shell: 1 spacer on left side, 1spacer on right side. 73mm bottom bracket shell: 1 spacer only on right side).
Thread new cups clockwise into left side and counterclockwise into right side.
Grease spindle surface and press right crank through right side.
Place left arm on to spindle.
Grease thread of arm cap and thread into spindle.
Lift the stop plate downwards and tighten the two left crank pinch bolts.