important: Nuts and bolts on your bike should always be tightened to the manufacturer's specifications.

How to Replace a Cartridge Bottom Bracket

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

Video updates

  • 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.

Related Links

Recommended Tools

Categories

Discuss this topic in the Bicycle Repairs and Mechanics Forum

New to forum, just signed-up, after reading an entry about constantly loosening crank-arm fixing BOLTS. In my case, my original BB, uses crank-arm fixing NUTS (original equipment, not jury-rigged), instead of BOLTS. I’m “dating” myself, but I’ve had this bike since new. I’m constantly re-tightening the nuts, every other ride, or worse, at times after a long ride. I have had difficult...

Read more

Anyone know how to remove the plastic cover at the base of the seat stem housing on a Trek Madone 9.2? The housing piece for the seat stem wobbles a little and I'd iike to tighten it. Assuming there's a screw underneath the covers.   IMG_2660.jpg (Size: 51.17 KB / Downloads: 104)   IMG_2659.jpg (Size: 44.51 KB / Downloads: 105) Thanks! Bill...

Read more

  varsity.jpg (Size: 152.97 KB / Downloads: 199)   varsity2.jpg (Size: 77.64 KB / Downloads: 200) Hi. This is my first post. I have a 1962 Varsity that I've enjoyed riding since I was 10. I'm in my 60's now and just want to putz around the neighborhood. In order to make the bike more comfortable I put a super big seat on it and 12" high handlebars. It's my Lazy-Boy on w...

Read more

I need to know what bottom bracket I have but I can fin a number or code on it to read it. Any experts in here, this is my first post.   006BA1F3-FE4D-4D22-85F0-095E72284B3D.jpeg (Size: 46.12 KB / Downloads: 57) ...

Read more

Custom Frame Headtube and Fork

Lastest post 1 week ago

G’day, I have a couple of questions. I want to install Fox 40 29” on a new custom made frame. Frame not made yet. The headtube will be straight headtube 44mm round 120mm or 135mm in length. What length would be best? I’m looking at zs44/28.6 zs44/30 headset. Would this be the right headset for the tube and fork? Also any tips on how to installing the fork and headset? Does the uppe...

Read more

I have what I take to be an adjustable quill stem, after some research. I had a bit of an incident in which a wheel temporarily became slightly loose, and I think the angle of the stem somehow moved closer to 180. The handlebars aren't at the right angle. Anyway, I've unscrewed the angle adjusting bolt, but I can't get this thing to budge. What do I do?...

Read more

Refitting a sturney archer wheel

Lastest post 2 weeks ago

I am having difficulty refitting a sturney archer 3 speed wheel. The chain on the indicator bar is coming out at the wrong angle by about 90 degrees. I have clearly reassembled incorrectly but I cannot see a way of assembling with the axial rotated by 90 degrees. Suggestions gratefully received. [attachment=1236]   71DD7E3C-8E11-4410-8239-13AB8963A4D3.jpeg (Size: 71.18 KB / Down...

Read more

Hi everyone. First post, posting from a phone while on a week-long bike tour. I forgot to pack a spare mountain bike tube [/w presta valve] and there are not many bike shops around, but we managed to pass by one in a remote area. Surprisingly, they only got Dunlop and Auto valve, no sign of Presta inthe necessary size. Was it a gamble to take Dunlop? Does it usually fit with the same rims as Prest...

Read more

Brake wire

Lastest post 3 weeks ago

Took my bike out after a couple of years only to remember that my left brake broke off while using it last and there is an unusual cable hanging from my bike that gets in the way sometimes, is it okay for me to cut it off? Will it affect the right brake?...

Read more

NordicTrack U300 Knocking

Lastest post 3 weeks ago

I'm hoping someone can help me figure out what is causing the knocking sound on my NordicTrack U300 stationary bike. Any help would be greatly appreciated! Here is a video of the knocking sound: https://1drv.ms/v/s!AnBkAt1Ty5oGiGDlEifMjPDihGr7?e=08qsm9...

Read more

Horrendous noises when pedalling

Lastest post 3 weeks ago

I have just started hearing horrendous noises when pedalling my 7 week old Trek Powerfly 4 ebike. The sound is worse than clicking and clunking and I can’t tell exactly where it is coming from. So have uploaded a video here: https://youtu.be/G3X2tLHk4Bk. Has anyone had similar or know what if could be? I’ve not heard these types of noises before....

Read more

Gear shift is stuck!

Lastest post 3 weeks ago

On both my bike handles, the gear shifts are stuck and I can’t move them. They’re currently stuck on gear 5 now (the highest). How do I fix it without needing a new gear shift?...

Read more

I bought a can of mineral oil from motorex and it came in 250ml aluminium can with big cap, and I need to fill my brake lever with that oil but I don't have syringe or bleed kit. How could I fill it up without syringe or bleed kit and tips? Anything similar to syringe that would work?   54e2f371.jpg (Size: 152.52 KB / Downloads: 54) ...

Read more

Freehub body change compatibility

Lastest post 4 weeks ago

I have a single speed kona unit with a formula dc52 hub (only single speed drive) and was wondering if anyone knew what freehub bodies were compatible so I can switch is to more then just a single. I would prefer not to have to buy a whole new wheel or rebuilding with a new hub. Thanks...

Read more

Hi, I'm new here. Just need some help right now for my grandson's Shocker 20 bike. The cable holder has come loose at the gripper handle and having trouble getting it back in. Any suggestions or where to get another 7 speed shifter for his bike? Thanks a lot. Sorry for not filling in any other "newbe" message, I'm currently baby sitting my other grandchild . That probably explains it all. 2...

Read more