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Hollowtech II bottom bracket removal and installation

In this article I’m going to explain how to perform a Hollowtech 2 bottom bracket removal and installation.

I had calculated my gear ratio, and swapped out the middle ring. In turn this caused the front derailleur to no longer work, which meant the outer ring had to go as well. I decided to add two new Specialités TA chainrings.

YouTube Tutorial

Removing the Hollowtech II crankset

The difference between a square taper bottom bracket and a Hollowtech II bottom bracket is that the spindle is integrated with the drive side crank.

Park Tool BBT-9 Bottom Bracket Tool
Park Tool BBT-9

To be able to remove the crankset, the non drive side crank needs to be removed first. You’ll need a specific tool for this. I’m using the Park Tool BBT-9 Bottom Bracket Tool.

loosen bolts

The drive side crank is fastened using two hex bolts. You’ll need to loosen them first.

remove adjustment cap

After the hex bolts are loosened you can remove the crank adjustment cap, which is used to press the crank onto the spindle. With one end of the tool you can take this cap off.

You should be able to remove the crank afterwards without any problems.

tap out crank

The drive side crank usually needs a light tap with a mallet before it’ll move. Make sure you remove the chain from any of the chainrings first. Chains don’t take lateral movement fondly.

Also make sure you don’t lose any spacers that sit between the Hollowtech II bottom bracket bearing and crank.

Hollowtech II bottom bracket removal

With the crankset out of the way you can focus on removing the Hollowtech II bottom bracket.

Hollowtech II bottom brackets are obviously threaded the same as traditional square taper bottom brackets. This means that to remove them you need to turn them into the direction the bike is facing. Clockwise for the drive side, and counterclockwise for the non drive side.

loosen hollowtech II bottom bracket

The Park Tool BBT-9 has a 16 splined part that fits snugly onto the cup of the bottom bracket.

hollowtech II bottom bracket tap

If the bottom bracket is stuck, a light tap with the mallet onto the bottom bracket tool will probably do the trick.

When removing the bottom bracket, again make sure you remember where the spacers are located so you put them in the right place when reinstalling.

hollowtech ii bottom bracket shell

In my case I cleaned up the bottom bracket shell and added the chainrings to the crank.

Hollowtech II bottom bracket installation

A Hollowtech II bottom bracket installation is basically the reverse of a Hollowtech II bottom bracket removal, with a couple of slight distinctions.

bottom bracket shell grease

The first one is that before installing the bottom bracket you want to add some grease on the threads of the bottom bracket shell.

With both sides sufficiently greased it’s time to install the bottom bracket. Rotating both sides backwards from the direction the bike is facing is now the way forward. Counterclockwise for the drive side and clockwise for the non drive side.

hollowtech ii bottom bracket installation

You’ll need to start with the drive side first. The fixing cup comes second. And don’t forget the spacers.

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