Hello Calvin Jones here, Park Tool Company.
This video will walk through the removal and installation of bottom brackets into threaded frame shells
including the 3 piece cartridge style, and designs that use threaded bearing cups.
Adjustable cup and cone-type bottom brackets are not covered in this video.
Also, for Campagnolo Ultra Torque systems,
the cups are not removed for bearing replacement as the bearings 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 what bottom bracket design you have.
The frame shells 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 bottom brackets feature a spindle integrated into the bearings as a self contained unit.
These are used on three piece cranksets which have separate left and right crank arms which attach to the integrated spindle.
Threaded thru-sprindle bottom brackets are comprised of a cup with a cartridge bearing.
These bottom 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,
3/8" drive ratchet or breaker bar,
Torque wrench,
and appropriate thread preparation.
We will begin with the cranks removed. See our cranks playlist for information on crank removal.
Especially if you are re-using the crankset, make note if your system used spacers between the frame and the cup.
We'll begin by removing the non-drive side bottom bracket cup.
But first, you will first 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 Parktool.com for a detailed description of the tools and parts they fit.
Use a 3/8 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 of bottom bracket cups have very shallow tool engagement.
Be especially careful to hold the tool against these bottom bracket fittings.
Once 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 a left hand thread.
It tightens to the left and removes 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 cup for markings stating 36x24 to confirm this standard.
Turn these counter clockwise 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.
Thread preparation is an important part of the installation process.
A new bottom bracket may come with a dry threadlocker already installed.
If so, it can be installed as is.
Another option is a liquid threadlocker, such as Park Tool TLR-1.
This lubricates the thread when tightening, and then expands and hardens as it dries, helping the cup stay tight.
Yet another option is an anti-seize compound, such as Park Tool ASC-1.
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 spacers on the new cup, if applicable, taking note of how the bottom bracket came apart.
The following is for threaded thru spindle bottom brackets, commonly used with 2 piece cranks.
The cups may be marked L and R for left and right side of the 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.
Turn carefully counterclockwise until you are sure there is no cross threading.
Tighten to manufacturer's specifications using a torque wrench. This can be between 24 and 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 kilograms of effort.
Insert any internal sleeve.
Install spacers as applicable to the non-drive side cup.
Thread it clockwise and secure to the same torque as the drive side.
For cartridge bottom brackets integrated with a spindle, note the thread direction.
Some but not all models will have left and right side markings.
These refer to the side of 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 care to install the spindle straight and not cross thread the bottom bracket
If it feels hard to turn or seems off in anyway, have a look at the opposite side.
Here you can see spindle is not centered in the shell, meaning it is cross threaded.
Remove, realign and try again.
Once you are sure it is going in straight you can use a tool.
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 bottom bracket, apply about 14 kilograms of force.
Repeat the process on the other side.
Reinstall the cranks. See our playlist for more information on your specific crank.
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