Installing a new external bottom bracket is pretty straight forward for the average DIY’er so long as you have the correct tools to hand.

The bottom bracket (BB) that we removed was an OE Shimano one which had been in the frame since I purchased the bike 5 years ago. How did I make it last this long? I’ll be writing another guide for that shortly.

After 5 years I’ve decided to treat the bike to a new BB and this time around I’m trying the new Superstar Components Angleset. This particular design uses angular contact bearings (like a headset uses) that are designed to handle loads from two directions (side to side as well as forward and backwards). In theory this will help prevent a common cause of BB bearing failures – too much preload during installation. However, in theory a correctly installed “regular” BB will last for ages too. Let’s see if I can make this one last 5 years!

You don’t need a professional workstand or a fancy workshop to do this – you can do this with the bike upside down in the living room (best to do this when your girlfriend/wife/mum/housemate isn’t around – trust me). All you need tool wise is the special tool for removing the cups, the preload tool and a 5mm allen key. You’ll also need some waterproof grease and some anti seize compound.

I popped along to Bourton Cycles to let Pete loose on my bike for this how to.

Slacken off the 2 x 5mm allen key pinch bolts on the non-drive side crank arm. It’s a good idea to undo each one evenly a little bit at a time.
Using the special tool (the Park tool shown here has it built into the end of the cup spanner) undo the bearing preload nut.
Sometimes you can push the axle out of the bearing cups, and sometimes you can’t. Here Pete taps gently with a soft-face mallet to remove the axle.
Using the correct tool, remove the driveside bearing cup. Take note of the directional arrows on the cups themselves. They will say “tighten” with an arrow. You’ll need to turn them the opposite way to undo them.
Repeat for the non-drive side cup, which turns in the opposite direction. Take note of the position and quantity of any spacers that may be installed behind either of the cups.
Clean and inspect the bottom bracket shell. Pay close attention to the threads. If any are stripped or damaged you’ll need to have the shell re-tapped – a job best left to a bike shop.
Now is a good time to clean and inspect your chainrings and replace any that are excessively worn. It’s also a good idea to make sure your chainring bolts are nice and tight, because while its nice to boast that you “sheared them all off with your amazing power”, its usually because one or more of them were loose to begin with!
Apply a smear of anti-seize grease to the threads on both sides of the bottom bracket shell.
Install the plastic tube into one of the bearing cups, remembering to use a little waterproof grease on the o rings as shown here. This helps to keep water out of the bearings.
Install the drive side bearing cup and any spacers into the frame and hand tighten. The cup will say “R” and will have a very useful arrow telling you which way to turn it. Take extra care not to cross-thread the cup!
Using the cup tool, tighten the cup. How tight to do this is hard to explain in text. You don’t want to over tighten this because you’ll squash the spacers and eventually strip the threads in the frame. “Nipped up pretty tight” probably covers this.
Repeat for the non-drive side cup.
Carefully insert the axle into the drive side cup. You can apply a little grease to the parts of the axle that make contact with the plastic top hats.
Handy tip this! When inserting the axle through the BB it’s a very good idea to support the plastic “top hat” with your fingers to stop it popping out or getting damaged. You might need a few gentle taps with the soft-faced mallet to fully seat it.
Use a little anti-seize on the splines if you have a steel axle and alloy crank arms. On Shimano cranks its difficult to install the non-drive side arm in anywhere but the correct position!
Grease the threads of the preload cap and tighten the cap until all the play at the bearing is removed, finger tight is generally as much as you need go. Check the cranks spin freely before securing the crank arm. Use a 5mm Allen key to tighten the crank bolts. Tighten the bolts evenly The bolts should be done up as tightly as stem bolts, to about 12-25Nm of torque.

It’s a good idea to go for a short ride and recheck that everything is tight.

Thanks to Pete Gowland for providing the hands, and Bourton Cycles for the use of the workshop and tools.

Using the special tool (Park tool shown here has it built into the end of the cup spanner) undo the bearing preloading nut

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