Tutorial - How to install / remove a bottom bracket

I was switching bottom brackets at the weekend and took a few pictures to create this tutorial for those who would like to change their bottom bracket.

Nothing is hard when you have the right tools so the first step is to actually buy the right tools. My bottom bracket was a Shimano and I was refitting a Shimano so here is what I need:

• A large 8mm allen key to remove the crank bolts
  
• A crank extractor to remove the cranks (£6.50 on Wiggle http://www.wiggle.co.uk/lifeline-crank-removal-tool/)
  
• A bottom bracket tool to remove the bb (£4.15 on Wiggle http://www.wiggle.co.uk/cyclus-bottom-bracket-tool-shimano/)
  
• A big adjustable spanner
  Depending on what you bottom bracket is, you will need a different bottom bracket tool / lockring tool. This tutorial is for Shimano but you'll get the idea of yours isn't Shimano type. Here are my tools:
  
  
  

Start by removing your chain or derail it off the chainring if you don't want to remove it. Give it all a good clean so you've got a nice working environment with no dirt to screw your threads.
Then the graft starts by removing the crank arm bolts on both sides with your allen key, just like this:

Once removed on both sides, grease your crank extractor tool (CET) and bolt it onto your crank arm. The inner part of the CET should be put in contact with the axle tip.

If you only have a big spanner (like I did), use it to screw it the outer part of the CET which will push the crank arm away from the BB - If you have more tools like a socket wrench, use it to screw the inner part of the CET will will push the crank arm away from the BB (this second method is more efficient).

At this point, you have removed your chain, crank arm bolts and crank arms. It's just you, the bottom bracket, the frame and your tools. So far, you are winning so have a beer.

Now use your Bottom Bracket Tool (BBT) + your spanner and slighly unscrew the no drive side, leave it in place at the moment so you can remove the BB nice and straight, like that:

Now you can remove your bottom bracket fully

Half of your work is done and your old bottom bracket is out!

You just need to put your new one in so at that stage, you should really know the BB you need - mine was british thread, 68mm shell and 107mm axle so that's what I got. I can't help with your chainline, but there is a thread for that here.

Start by cleaning all the threads and then greasing it all properly with good teflon based grease or better then put the non drive side cup in place with your hand.

Then insert your fresh bottom bracket by hand so it is nice and straight, through all the way through the non drive side.

As per previous pictures, use your BBT to tighten the bottom bracket in place, starting with the drive side then the non drive side. As a guideline, tight is tight, too tight is fucked so don't go nuts.

Place your crank arms back in place and fit your crank arm bolts - tight.

Once again, you've done it - saving you about £20 from your local bike shop (including the tools you've bought).

Have a beer!

Cheers

Vince