How to Disassemble a Bicycle Crank
Whether you want to clean, overhaul or replace your bicycle crank, you must first disassemble the crank. A bicycle crank consists of a spindle that passes through the bottom bracket of the bike frame. The spindle holds two bearing cages in place on either side. A bearing race on each side of the bracket provides a solid foundation for the bearings to ride on. A lock ring holds the crank together. On many modern bicycles, these components are incorporated into a sealed cartridge. With the right tools, and a little time, you can disassemble your bicycle's crank at home.
Place your bicycle in the work stand.
Shift the front derailleur to the smallest chain ring.
Remove the chain and place it on the bottom bracket of the bicycle frame.
Crank Arm Removal
Hold onto the crank arm with one hand and remove the crank-arm tightening bolt with either the 8 mm Allen wrench or 14 mm socket wrench.
Completely extend the crank puller by turning the threads counterclockwise. Thread the outer threads of the crank arm puller into the crank arm. While holding the crank arm, turn the internal driver of the crank arm puller clockwise until it stops.
Place the large adjustable wrench on the flat sections of the crank arm puller. Hold the adjustable wrench in place and place the 16 mm wrench on the internal driver. Turn the internal driver clockwise until the crank arm comes off the spindle.
Repeat this section to remove the other crank arm.
Remove the Crank
Loosen and remove the lock ring on the left side of the bike counterclockwise with the lock ring wrench.
Place the bottom bracket wrench on the left bearing race and turn it counterclockwise to loosen the race. Unthread the bearing race and remove it from the bottom bracket.
Pull the crank spindle and the bearing cages from the bicycle frame.
Remove the drive side bearing race by turning it clockwise with the 36 mm wrench.
Disassemble a Cartridge Bottom Bracket
Place the spline bottom bracket tool on the drive side of the cartridge.
Turn the spline bottom bracket tool clockwise with the adjustable wrench to loosen the cartridge. Unthread the cartridge and remove it from the bottom bracket.
Turn the non-drive side of the cartridge by hand counterclockwise to loosen it and remove it from the bottom bracket.
- shanedhumphreys/iStock/Getty Images