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HowTo - Remove a square taper bottom bracket

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    HowTo - Remove a square taper bottom bracket

    Just a quick post this evening on removing a square taper bottom bracket. There are several styles of bottom brackets. The process is them all is similar. You might need a slightly different tool than the one I use in this example

    The bottom bracket is the part of the bike where the crankset attaches to frame. The cranks and chainrings rotate on a spindle that passes through the bottom bracket shell.
    Click image for larger version  Name:	1. BB Shell.jpg Views:	1 Size:	397.4 KB ID:	27407

    The bottom bracket consists of a support cup, cartridge, and spindle.
    Click image for larger version  Name:	2. BB Assembly.jpg Views:	1 Size:	172.2 KB ID:	27408

    We need to remove the cranks from the spindle. In a square taper bottom bracket the spindle is tapered. A single bolt at each end of the spindle presses the crank onto the spindle shaft. Removing the cranks is a two step process.

    We remove the spindle bolt.
    Click image for larger version  Name:	3. Spindle Bolt.jpg Views:	1 Size:	581.3 KB ID:	27409

    We must extract the crank from the spindle.

    I recommend spending the money to buy the proper tools to work with your style of cranks and bottom bracket. These components are subject to the full force of the rider stomping on the pedals. They are directly in the line of fire for any grit thrown from the front tire on a wet ride. The are often stuck tightly. Makeshift tools are likely to strip splines and damage fragile bearings. You might end up paying your local bike shop for the striped of damaged component.
    Click image for larger version  Name:	4. Crank Extraction Tool.jpg Views:	1 Size:	326.1 KB ID:	27410
    Click image for larger version  Name:	5. Using Extraction Tool.jpg Views:	1 Size:	460.5 KB ID:	27411

    Once the cranks are removed we need to remove the bottom bracket cartridge from the right side of the bike and the bottom bracket support cup from the left side of the bike. There is a good cheat sheet for looking up which way to turn to remove the cartridge and support cup at
    Click image for larger version  Name:	6. Park bb Removal Tool.jpg Views:	1 Size:	391.3 KB ID:	27412

    One quick word of warning, as I said earlier, bottom brackets can be stuck tight. My wrench for bottom bracket work is an old harbor freight torque wrench. It has a nice 18 in. handle for plenty of torque. If that doesn’t cut it, I use and ancient wrench that probably started it’s life in the 1800’s on a steam locomotive. It is not pretty but the handle is 36 inches long.
    Click image for larger version  Name:	7. Removing BB.jpg Views:	1 Size:	378.7 KB ID:	27413

    If you don’t have a wrench that long another good option is to put the bottom bracket tool in a bench vise and set the bike on top of tool and turn to frame to generate the torque.

    With the bottom bracket off we are ready to continue with the next step in the build.

    I just came across . It is an excellent article with more detail.

    Happy Building
    Last edited by funwithbikes; 02-14-2017, 11:10 AM.