How to Remove Bottom Bracket

This guide covers the steps necessary to remove a bottom bracket from a bicycle. Whether you’re performing maintenance or upgrading components, learning how to do this yourself can save time and money.

Tools You’ll Need

• Bottom bracket tool
• Crank puller
• Allen wrench
• Adjustable wrench (or a set of spanners)
• Bicycle stand or a secure method to hold the bike in place
• Penetrating oil (optional, for stubborn components)

Preparing Your Bike

Start by placing your bike in a stand or securing it so it won’t move during the process. Shift the chain onto the smallest chainring to reduce tension and make crank removal easier. If your bike has a chain guide or front derailleur, consider removing it to provide better access to the cranks and bottom bracket. Clean the bottom bracket area to remove dirt and grime, which can make it easier to work and help prevent debris from entering the frame.

Removing the Cranks

To remove the cranks, start by locating the crank bolts. These are typically found in the center of each crank arm. Use the appropriate size Allen wrench to loosen and remove these bolts. If the cranks are stuck, apply a penetrating oil and wait a few minutes before trying again.

Once the bolts are removed, use the crank puller tool. Thread the crank puller into the crank arm where the bolt was. Turn the handle of the crank puller until the crank arm is extracted from the bottom bracket spindle. Repeat this process for the opposite crank arm.

Identifying Your Bottom Bracket Type

Different bikes use different types of bottom brackets, so you’ll need to determine what type you have before proceeding. The most common types include threaded bottom brackets and press-fit bottom brackets. Threaded bottom brackets are screwed into the frame, while press-fit bottom brackets are pressed into place. Check your bike’s manual or look up the specifications online to identify your bottom bracket type.

Removing a Threaded Bottom Bracket

If your bike has a threaded bottom bracket, you’ll need a bottom bracket tool that matches the specific type and size used on your bike. Attach the bottom bracket tool to an adjustable wrench or handle. Insert the tool into the bottom bracket cups.

To remove the right-side (drive-side) cup, turn the tool counterclockwise. This side is often reverse-threaded, so confirm this by consulting your bike’s documentation. Turn the tool until the cup is completely unscrewed and removed. Repeat this process for the left-side cup, but turn the tool clockwise as this side is generally normal-threaded.

Removing a Press-Fit Bottom Bracket

For a press-fit bottom bracket, the process is slightly different. Begin by tapping around the edges of one side of the bottom bracket with a mallet and a flat-ended tool like a screwdriver or a wooden dowel. This will loosen the bond between the bottom bracket and the frame. Apply even pressure around the circumference to avoid damaging the frame.

Once one side is sufficiently loosened, use a bottom bracket removal tool designed for press-fit systems. Insert the tool into the bottom bracket shell and tap it with a mallet to push the bottom bracket out of the frame. Repeat this process for the other side.

Cleaning and Inspecting

With the bottom bracket removed, clean the bottom bracket shell on your bike frame to remove any old grease, dirt, and debris. Inspect the shell for any signs of wear or damage. If you notice any issues, consider consulting a professional before installing a new bottom bracket.

Conclusion

Removing a bottom bracket may seem daunting, but with the right tools and a bit of patience, it can be done efficiently. This guide covers the essential steps and tips to safely remove your bottom bracket. Always refer to your bike’s documentation for specific instructions related to your model, and don’t hesitate to seek professional help if needed.