Bicycles/Maintenance and Repair/Tools and Supplies/Bottom Bracket Tool
A bottom bracket tool is specifically designed to remove and insert the bottom bracket of a bicycle.
Bottom brackets are, unfortunately, one of the less standardised parts of a bicycle. Over the years manufacturers have come up with many different approaches to providing gripping surfaces for the bottom bracket to be inserted or removed. A typical repair shop will, correspondingly, have a variety of tools available for different styles of bottom bracket.
One of the older and more common systems uses the combination of a lock ring remover and a pin wrench. the left bearing cone is removed in order for the bearings and axle to be removed.The bearing cone has two shallow holes drilled into it. When a pin wrench is inserted into these holes, the bearing cone can be threaded in or out.
The lock ring is a circular nut used to prevent the left bearing cone from loosening by accident. The lock ring remover is inserted into one of several notches in the lock ring in order for it to be removed.