How to Remove and Install Bottom Brackets - Threaded Shell (BSA, T47, Cartridge, etc.)

Calvin Jones here , Park Tool Company .

This video will walk through the removal and installation of Bonner brackets into threaded frame shells including the three piece cartridge style and designs that use threaded barring cups , adjustable cup and cone bonum brackets are not covered in this video .

Also for cap no ultra torque systems , the cups are not removed for bearing replacement as the bangs are installed on the crank spindles .

See our full bottom bracket playlist here .

If you have one of these bottom bracket styles or if you're unsure of the bottom bracket design , you have the frame shell for the bottom brackets .

In this video use internal threads to accept bearings .

The bottom brackets that use these threads can be one of two styles cartridge Bonner brackets feature a spindle integrated into bearings as a self contained unit .

These are used on three piece crank sets which have separate left and right crank arms which attach to the integrated spindle threaded through spindle .

Bonner brackets are comprised of a cup with a cartridge bearing .

These Bonner brackets are threaded into the frame and then the crank spindle is passed through the bearings .

Typical tools and supplies include an appropriate bottom bracket tool to fit the cup .

A three H drive ratchet or breaker bar .

A tar rench , an appropriate thread preparation .

We will begin with the cranks removed .

See our crank playlist for information on crank removal , especially if you are reusing the crank set .

Make note of your system , use spacers between the frame and the cup will begin by removing the non drive side , bottom bracket cup .

But first , you will need the proper tool .

There are many options to find the correct tool .

You should count how many notches are on the tool fitting , then measure the outside diameter with a caliper .

See this page on park tool dot com .

For a detailed description of the tools and parts , they've hit a 38 inch drive ratchet or breaker bar to drive the tool , make sure the tool is fully and evenly engaged on the tool fitting , apply pressure to the tool while loosening so it does not slip off under heavy load .

Some models , the bottom bracket cups have very shallow tool engagement be especially careful to hold the tool against the bottom bracket fitting , the cup is removed , pull out any protective sleeve that is still inside the shell .

Next , remove the drive side cup for shells with the common English threading , the drive side is the left hand thread .

It tightens to the left and moves to the right turn the drive side clockwise and remove it .

Note for bikes that use the Italian threading standard .

Both non drive and drive side are right hand threads , inspect the cups for markings stating 36 by 24 to confirm this standard , turn these counterclockwise to remove .

If after you remove the cups , you find that they look like this and the bottom bracket shell is not threaded .

You have a thread together style bottom bracket .

See this video for the proper installation procedure , wipe the bottom bracket , clean of dirt .

The interface between the crank and the bottom bracket can be complex with a lot of things to consider for parts compatibility and availability .

Consult the component manufacturer or contact your local bike shop .

Preparation is an important part of the installation process .

A new bond bracket may come with a dry thread locker already installed if so it can be installed as is another option is a liquid thread locker such as Park tool T L R one .

This lubricates the thread when tightening and then expands and hardens as it dries helping the cup stay tight .

Yet another option is an any seized compound such as park tool ac one , it provides a very durable and long lasting lubricant for the threads .

But if you have nothing else , at least use some grease .

A good technique is to put the preparation inside the shell and spread it around that way .

When you thread the cup in the excess doesn't back up against the cup and make a mess .

Install spaces on the new cup .

If applicable , taking note how the bottom bracket came apart .

The following is for threaded through spindle bottom brackets commonly used with two piece cranks .

The cups may be marked L and R for left and right side of bike .

You may also find directional arrows indicating which way to turn by hand , begin to thread in the drive side cup .

Remembering it is a left hand thread carefully counter clockwise until you are sure there is no cross threading to manufacture specification using a tore .

This can be between 24 50 Newton meters .

If using a hand wrench , use perceived effort for a wrench held at 20 centimeters from the bottom bracket .

Apply about 18 kg of effort .

Insert any internal sleeve install spacers as applicable to the non drive side cup , put it clockwise and secure to the same torque as the drive side for cartridge bottom brackets integrated with the spindle note the thread direction , some but not all models will have the left and right side markings .

These refer to the side of the bike , not thread direction , install the bottom bracket with the flange side .

First .

In this example , the flange is on the right , which is the drive side , use car to install the spindle straight and not to cross thread the bottom bracket if it feels hard to turn or seems off in any way , have a look at the opposite side .

Here , you can see the spindle is not centered in the shell , meaning it is cross threaded , remove realign and try again .

Once you are sure it's going in straight , you can use the tool to secure this side .

Typical torque is 25 to 30 Newton meters .

Consult the manufacturer .

If in doubt if using a hand wrench , use perceived effort for a wrench held at 20 centimeters from the Bonner bracket .

Apply about 14 kg of force .

repeat the process on the other side , reinstall the cranks share a playlist for more information on your specific crank .

Thanks for watching this repair health video from Park Tool .

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