How To Replace a Cartridge Bottom Bracket

Demonstrates how to remove and install a sealed cartridge bottom bracket.

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01:30 - The torque specification are actually 25-30 ft-lbs, or 300-360 in-lbs. Check with the manufacturer for exact products specs.

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 25-30 foot-pounds of pressure (300-360 inch-pounds) using a torque wrench. Torque specifications vary, so it’s a good idea to check the manufacturer’s website for their exact product specifications.

Now you can finish tightening the left side clockwise until it is nice and snug.

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14 Responses to “How To Replace a Cartridge Bottom Bracket”

matt on February 24th, 2008 11:21 am

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.
Alex on February 25th, 2008 8:49 am

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…
matt on February 25th, 2008 3:09 pm

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.
Alex on March 1st, 2008 2:47 pm

Hi Matt,

As far as I know there are no negatives to using bb-mount front derailleurs.
Mark Brian on March 22nd, 2008 9:24 am

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
Alex on March 22nd, 2008 11:48 am

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).
mark on March 24th, 2008 2:43 pm

Thanks
John on July 18th, 2008 10:00 pm

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.
Grant on September 25th, 2008 10:31 am

If only all bottom bracket lockrings came off that easy!!!!!!!! Any tips for ones that won’t budge?
Matt B on October 20th, 2008 5:46 pm

Thanks for the video Alex – wish I’d watched it before installing my bb; I overtightened and cracked the (plastic) lockring, thinking it had to be tightened until no thread was visible
elmonica on December 6th, 2008 6:07 pm

One thing I experienced is when I used that Park tool BBT-22, the splines on the drive side don’t go very far into the cartridge. I tried using a socket wrench as well and I had to securely hold the BBT-2 against the cartridge while turning my wrench. Hopefully I tightened it enough.
Danny Nichols on February 2nd, 2009 11:20 am

I like your site. Videos are to the point and make sense. I have been my own mechanic for years. Its nice to be able to find the answers to any problem I am not 100% positive of. Very nice.
larry belli on March 9th, 2009 10:54 pm

I have a 2008 raleigh mohave 8.0 with a octalink crankset. I would like to upgrade to a better one. I’ve heard different stories about Q factor and you name it. Could you suggest a logical upgrade?

thx
Alex on March 11th, 2009 2:52 pm

I’m not too familiar with the octalink or Q factor cranks… I’ll have to pick some up. In the meantime I would post something in the forums to see if others have any suggestions.