10. How to Replace a Cartridge Bottom Bracket

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

IMPORTANT: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.
How to Replace a Cartridge Bottom Bracket
DVD Vol. 1 DVD Volume 1
This video is available on DVD


  • 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.


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.


Related Links

Discuss this topic in the Bottom Bracket Forums

04/06 Fix a bottom bracket that loosens the pedal


My bike started recently having a problem where every few hundred meters my pedal arm gets loose and shaky, and I have to stop and tighten again.

I've completely opened and cleaned the bottom bracket and I've replaced the ball bearings (not the cages). The situation has improved, but the pedal still gets loose.

I'm not sure what to try next in order to fix it:
When I replaced the bottom bracket it seemed not too worn out, and only the point where the ball bearings touch on it had lost the paint, and it had signs of fatigue where the crank ... Read more >>

03/17 Cup Wrenchs - Which ones do I need?


Hopefully someone can identify the wrenches I need:

thanks in advance.

[Image: twwLjh1.jpg]...

03/02 BB question

I have a Origin 8 Adrenaline frame - Info on the frame: 65mm BB Drop?. I bought SRAM red components. SRAM Red carbon TT crankset 130bcd BB30. I'm completely new to bike building. I want to get all the parts together. not sure exactly what BB I need. BB30 but, not sure of sizing. Thanks for your help!... Read more >>

01/28 Replacing my BB/crank

I'm fairly new to bmx terminology so bare with me.

My old bottom bracket and crank was rusted and the threads were severely stripped so I decided to replace them. The new crank, spindle, and bearings I bought are all 19mm and the old ones are 22mm or something. I took the old bearing cups off the rusted bearings to use with my new ones, but they don't fit, so I'm assuming you have to buy new bearing cups specifically for the size of bearing? (I know this is probably a dumb question) And are all bearing cups the same circumference on the outside?

My other question i...

01/15 Coaster brake bike pedals don't turn

Newbie here, so forgive me if I picked the wrong area for my problem.

Kids 16", single speed, coaster bike. Got for Christmas from Wal-mart b/c he LOVES Superman. http://www.walmart.com/ip/16-Huffy-DC-Superman-Boys-Bike/27831881
Worked fine until today! I didn't believe my son at first since he's a little small for the bike. Pedals no longer turn or turn with great difficulty. I can barely move them by hand forward or backward. At first it would work backwar... Read more >>

11/23 1977 Raleigh 26tpi BB and Chainset

I've had a Raleigh Silver Jubilee since it was new in 1977. The chainset needs replacing. I have not been able to find a replacement that gives anything like the correct chain line. Can anyone help?

The alternative would be a shorter spindle. The original was a 126mm 5s. I can't find anything shorter to fit the 70mm frame. It probably needs to be about 116 mm. Help?

If a shorter spindle is not available I could replace the existing bearings with a cartridge but I can't find anything 26tpi for a 70mm shell. What would you suggest?... Read more >>

11/11 Found spec sheet, but what BB length do I need for my crank?

Looking to rebuild the entire drive train on an old frame. To start, I'm looking at the Shimano Tourney A070 double crank set. But I can't make head or tails of the spec sheet I've found for a compatible BB? Shimano's recommendation is the BB-UN26, for which there are at least 5 different lengths (from what I can tell from some ... Read more >>

11/09 Upgrading to a cartridge BB

Hey folks! First post. I'm working on a salvage project, re-building a road bike from an old frame. I want to put a cartridge BB in it, but I need some help figuring out sizing, etc. Disclaimer: I'm terrible with brands, but good with the mechanical side of things; you may have to hold my hand a little through this one.

I've looked at some of the stuff from Sheldon Brown, but it's really going over my head. Or maybe my mind is just saturated... I've been doing a lot of reading...

Anyway, the old spindle was a 3T, which I believe means I'd be best suited picking up a 1... Read more >>

10/19 Replacing crank / BB

Hi all,

I've got an old bike that I've decided to finally give some TLC - can't bear to part with it. It's a year 2000 Giant ATX 830 mountain bike.

Not my bike, but this is what it looks like:
Giant ATX 830

It sports a 68mm, English thread BB, and a 3x8 Diamond taper crankset. I've measured my chainline to be approximately 49mm - 50mm, from the centre of the frame to the centre of the middle cog on my crankset.
...

09/26 Bottom bracket assembly keeps loosening up?

Hey Guys,

Replaced my bottom bracket a couple month's ago from a english style to a sealed cartridge. My problem is that it keeps loosening up. The inside tightening nut, next to the chainrings, is the one that is coming loose. I have tightened the mess out of it at least 3 times now and it has loosened up again. Makes a sqeak on the down stroke. My bike has the front derailleur that is held by the inside tightening nut of the bottom bracket.

I followed the directions and put grease on the threads of the bottom bracket and assembled it and tightened, but still it come... Read more >>

09/22 Titanium BB crack repair

Hi all,

I'm new here, but thought I would share my recent experience trying to repair a crack in my Merlin Taiga frame. The crack originated in the weld between the BB and the seat tube during a cycle tour in southern Chile. Two attempts at welding were unsuccessful and it was suggested by several shops that I junk the frame. Having $800+ invested in S&S couplers plus many thousands of miles of love and companionship, I couldn't do it, so I set out to find a repair on my own. My dad is a machinist and we contemplated a mechanical fix - some sort of brace or clamp, bu... Read more >>

09/06 Old to new

I have a 1994 GT that I have added many upgrades to. I would like to get rid of the old FC-TY21 crank set. I really like the hollow tech parts like Deore or DLX. Can I swap this stuff in? Spindle length on the original parts is supposed to be 122.5 mm per http://www.shimano.com/publish/content/global_cycle/en/us/index/tech_support/tech_tips.download.-Par50rparsys-0... Read more >>

08/25 How to choose the right bottom bracket?

Hello everyone,

I am custom building my own bike, basically I am building a bike from scratch. I've got the frame and I have measured the shell width which is 68mm. I have bought a single speed 44 Tooth chainset/crankset. Now how do I know which size bottom bracket would fit the crankset? Would I have to buy 3 or 4 different size bottom brackets and try each one out to get the right bottom bracket? Somebody please help.

Thank you
Ibs...

07/17 BB? 1999 Schwinn moab

i believe i need to change my BB, when i pedal on a hill or pedal with power i hear a creaking sound. ive checked my handle bars, pedals as recomended in another thread.

does any one know a suitable replacement BB?

i also want to replace 1 ring( the biggest one) on the chain ring.. should i ? or should i just replace the whole crank set?

i would like to have a bigger gear when i put the fD to "3"

would i need to replace my chain as well?


can any one tell me about this bike. i havent found much about it ... Read more >>

07/03 One Piece Crank BB - bearing trouble

Hi Guys, first post here. I've been using the site to help me maintain my bikes for a few years now.

I'm visiting the US for a bit and picked up a bike on craigslist (a huffy road bike early 80s I think), only cheap but on a short test cycle it felt solid. I did notice the crank had a bit of a wobble. Anyway I bought it and figured I'd put it into the LBS to overhaul the BB, new bearings and grease, etc.

Picked the bike up from LBS and had a ride, the crank is solid now (no play), but I think maybe they over tightened it or messed up the bearings as I'm now getting t... Read more >>

New Thread
How to Replace a Cartridge Bottom Bracket
Repair Guide / Help Forums

Free Email Updates: