This tutorial will demonstrate how to remove and install a sealed cartridge bottom bracket, found on most modern bicycles. You’ll need to remove both cranks first, so be sure to refer to last week’s crank removal and installation tutorial before you begin.
Required Tools
For this job you’ll need a splined bottom bracket tool and a 32mm headset wrench, or a large adjustable wrench.
Components
A cartridge bottom bracket usually has two main components. The cartridge contains the sealed bearings and spindle, and is usually threaded into the right (or drive side) of your frame. The lockring supports the opposite end of the cartridge and is usually threaded into the left (or non-drive side) of your frame.
Bottom Bracket Removal
Remove the drive side first, using the lockring tool and wrench. On most bikes, the drive side has a left-hand thread, so you’ll need to turn your wrench clockwise to loosen. Once the drive side is removed, the non-drive side should easily loosen and unthread by turning counter-clockwise.
Before installing the new bottom bracket, carefully clean the threads on the inside of your frame, and then apply a thin layer of waterproof grease to the threads on both sides of the frame.
You’ll notice that most bottom brackets have an ‘L’ and ‘R’ written on them to assist in installation.
Bottom Bracket Installation
To install, first thread the new lockring part way into the left side of the frame by turning it clockwise. Don’t tighten the left-side yet.
Thread the cartridge all the way into the right side of the frame by turning it counter-clockwise. Tighten it with about 60 pounds of pressure, or 360 inch pounds using a torque wrench.
Now you can finish tightening the left side clockwise until it is nice and snug.
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Some people have said that you need to remove the lockring before the BB. How come you do it the opposite way round, and does it matter.
Hi Matt,
No I don’t believe that matters. In all my years as a shop mechanic I never heard of that being an issue. However, I’d be happy to hear any reasons why it might be better the other way around…
Hi Alex, I have not yet come across a reason not to do it your way round but I always learned it to be the other way. I think the only thing that would make it matter was if you had a bottom bracket fitted front mech. Do you have any negatives on front mechs being fitted this way, and would you change it to a clamp on one.
Hi Matt,
As far as I know there are no negatives to using bb-mount front derailleurs.
I have purchased a frame without a cartridge bottom braket.
How do I measure the whole so I can purchase the correct cartridge??
tks
Mark
Bottom bracket sizing is tricky. Sheldon Brown’s website has a comprehensive sizing database here:
http://www.sheldonbrown.com/bbsize.html
Or you could take your bike down to the local shop for sizing. That would probably be best, as they can better assess not only the bb shell size in your frame, but also the correct spindle length you will need (depending on the type of crank arms you have).
Thanks
Thank you for making this video. After watching it a few times, I was able to remove and inspect and reinstall my BB. and it is working fine now. No more clicking when I ride.