The Shimano Dura-Ace crank system is an external bearing crank system for bicycles. While traditional bearing sets consist of a separate bearing that sits within the bottom bracket, the Shimano Dura-Ace crank integrates the bearings, crank and spindle. The bearings are external to the bottom bracket, mounted within the bearing cups that thread into the sides of the bottom bracket. Removal of a Dura-Ace crank system requires the use a special tool the fits onto the splines on the outer rim of each bearing cup. With this tool, you can quickly remove the system from your bicycle at home.
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Place your bike in a bicycle work stand. Remove the drive chain from the front chain ring and place it over the bicycle frame's bottom bracket.
Loosen the two Allen screws on the pinch bolt of the non-drive side crank arm. Use the special cap tool to remove the arm cap. Slide the crank arm off the crank spindle. If the crank arm sticks, gently tap it with a plastic mallet to loosen it.
Pull the drive side crank arm and chain ring out of the bearing cups.
Turn the non-drive side bearing cup clockwise with the Shimano removal tool. Remove the bearing cup from the bottom bracket.
Turn the drive side bearing cup counter-clockwise with the Shimano removal tool. Remove the bearing cup from the bottom bracket of the bicycle frame.
Remove the inner cover and O-rings from the bottom bracket.